CN117941173A

CN117941173A - Open waveguide antenna and system with open waveguide antenna

Info

Publication number: CN117941173A
Application number: CN202280062027.6A
Authority: CN
Inventors: 塞尔吉奥·克拉维霍; 约翰·桑福德; 卡尔·爱德华·施普伦托尔; 迪尔克·巴尔斯; 贾里德·肯尼斯·斯平克; 普拉莫德·斯里尼瓦斯·巴特
Original assignee: Rogers Corp
Current assignee: Rogers Corp
Priority date: 2021-09-14
Filing date: 2022-09-14
Publication date: 2024-04-26

Abstract

A waveguide antenna system comprising: an electromagnetic EM transition section having a transition region, having a signal feed interface and an open waveguide section, the EM transition section configured to couple EM energy from the signal feed interface to a guided waveguide mode of the EM energy via the transition region to the open waveguide section; and a leaky waveguide antenna portion configured and arranged to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support electromagnetic energy transfer from the signal feed structure to the leaky waveguide antenna portion.

Description

Open waveguide antenna and system with open waveguide antenna

Cross Reference to Related Applications

The present application claims the benefit of U.S. application Ser. No. 17/943,450, filed on day 2022, month 9, and 14, which claims the benefit of U.S. provisional application Ser. No. 63/244,018, filed on day 2021, month 9, and 7, and which claims the benefit of U.S. provisional application Ser. No. 63/286,839, filed on day 2021, month 12, all of which are incorporated herein by reference in their entirety.

Background

The present disclosure relates generally to open waveguide antennas, and more particularly, to open waveguide antenna systems.

Previous generations of millimeter wave systems have been built with several special purpose MMIC (monolithic microwave integrated circuit) devices, which typically include a transmitter integrated circuit, a receiver integrated circuit, and a local oscillator circuit for synchronizing these systems together. An example of this construction is the ARS-4A long range radar sensor of the Continental company (Continental), examples of which can be found at the following websites: http:// img009.hc360.cn/k2/M0A/BF/43/wKhQxVq53tueemCQAAAAACS5hks768.pdf. Due to the distributed nature of the transmitter and receiver MMICs in these systems, the distance between the radiator and the MMIC can be reduced, resulting in an insertion loss that is tolerable despite the electrically large antenna aperture produced by the radar. Recently, CMOS MMIC devices that combine TX and RX functions into a single chip have become available. These systems are advantageous from a cost perspective, which not only reduces die costs, but also reduces assembly and manufacturing costs for radar manufacturers. Which has the effect of concentrating the MMIC and increasing the transmission line distance between the antenna and the MMIC. Additionally, this concentration reduces the complexity of RF signal routing between devices.

Both the trends of extending the transmission lines and reducing the complexity of routing signals have made alternative methods of connecting antennas to MMICs more attractive. A common RF interconnect approach is to use etched traces on a printed circuit board. The transmission line structure is typically a microstrip (the signal layer is separated from ground by a dielectric) or a coplanar waveguide (the microstrip with ground structure is beside the trace on the signal layer). This type of transmission line has an insertion loss of about 1dB per inch at 79GHz when produced on a "best in class" PCB material, and about 2dB per inch at 79GHz when produced on a conventional PCB material.

As MMICs become more integrated and the number of routed RF transmission lines on the PCB decreases, old transmission structures become more suitable. The waveguide was theoretically explored in the 90 s of the 19 th century, and was actually employed since the 40 s of the 20 th century. At 79GHz, a rectangular waveguide will exhibit an insertion loss of about 0.25dB per inch. In practice, a 79Ghz system applied to a3 inch long transmission line will consume 50% of its power in a microstrip line built on the same class of best laminates, 75% of its power on a conventional PCB, but only about 16% of its power in the waveguide. In radar systems, this loss difference is seen from both the MMIC transmitter block to the antenna and from the antenna to the MMIC receiver block. Thus, the "two way" loss is twice the number of losses above. This makes reducing losses more attractive to the designer of the radar system.

For designers employing waveguide feed networks in millimeter wave radar or communication systems, there are three additional considerations that determine system architecture and performance. First how power is transferred from the MMIC to the waveguide (transition), second how power is transferred from the waveguide to free space (antenna), and finally, for most systems, cost is a critical consideration in addition to system performance.

For power transfer between an MMIC and a waveguide, two main approaches have been described.

The first transition method is to use the transition from the package to the printed circuit board. The transition typically involves several sub-transitions. Power is first transferred from the semiconductor die to a fan-out layer or redistribution layer in the device package, and then power is transferred from the redistribution layer to the printed circuit board, typically through a ground-signal-ground (GSG) configuration implemented in a ball grid array. The signal/power is then routed through a grounded coplanar waveguide structure, transitioning to a microstrip structure, which then excites a radiator for emission into the waveguide. This method has the advantage of utilizing mature technology, but also has the following drawbacks: (i) The requirement to create a controlled impedance structure on the main printed circuit board; (ii) The cost and supply chain complexity of utilizing low loss PCB materials on the main printed circuit board; and (iii) multiple sets of transition losses: MMIC to RDL, RDL to BGA, BGA to PCB, PCB to waveguide, wherein these transitional losses partially negate the benefits of utilizing waveguides, particularly for short transmission line lengths.

A second transition method that has been proposed is to launch directly from the package into the waveguide. An example description ：https://www.ipcei-me.eu/wp-content/uploads/2020/11/4-Pack-Trends-for-mm-wave-Radar-Infineon-Maciej-Wojnowski.pdf. of the method is provided on page 30 of the following document, which counteracts the following disadvantages of the first method: (i) The requirement to create a controlled impedance structure on the main printed circuit board; (ii) The cost and supply chain complexity of utilizing low loss PCB materials on the main printed circuit board; and (iii) a net reduction in transition losses, i.e., BGA to PCB. It is expected that the reduction in PCB cost and supply chain complexity is attractive to developers of millimeter wave radar and communication systems.

In the design of millimeter wave radar or communication systems, antenna selection and design are important considerations. In radar systems, there are two main use cases: first, radar systems intended to travel over long distances; and second, radar systems that operate across shorter distances but have a wider coverage area are required. In the field of automotive sensors, these radar systems are often referred to as long-range radars for functions such as adaptive cruise control and corner radars or short-range radars for functions such as blind spot detection, lane change assistance or parking assistance.

Long range radar is generally expected to cover lanes in front of or behind a vehicle. Corner radars are used to complement the coverage of long range radars in order to provide 360 degree coverage around the vehicle. It is also desirable that the coverage has redundancy, so corner radars will typically attempt to cover 120 degrees of azimuth field of view, while long range radars may typically cover 60 to 90 degrees of azimuth field of view. For reference, the elevation plane is generally oriented in the elevation direction of the vehicle, while the azimuth plane is perpendicular to the elevation plane. In situations where the vehicle is expected to operate at a higher level of autopilot, such as SAE level 3 or SAE level 4 autopilot, the vehicle may also employ a mid range radar that operates with azimuth coverage between that of a corner radar and that of a long range radar. It may also be desirable to produce corner radars with enhanced range for the total cost of ownership of the vehicle, eliminating the need for a centered equidistant radar.

The antenna architecture is typically selected first for its field of view and then for its bandwidth, although the type of antenna will also depend on the type of antenna feed. In a printed circuit board based feed network, the antenna is also typically formed on the PCB, whereas in a waveguide structure it is desirable to use a construction method similar to the way waveguides are produced. Polarization is another consideration that designers use in selecting antennas. Finally, sidelobe levels are important in many radar and communication systems. For long range radar antennas with a small field of view (related to the azimuth half-power beamwidth of the antenna), series fed microstrip patch antennas are typically used. The parallel series feed lines may be used to further reduce the field of view, thereby increasing the gain of the antenna and subsequently the range of the radar system.

To achieve a wide field of view, comb lines (sometimes referred to as side feed patches) or slotted antennas are typically employed.

A Substrate Integrated Waveguide (SIW) plus slotted antenna may also be employed with a printed circuit board feed network. Slotted antennas will typically exhibit some of the widest field of view, but with additional PCB manufacturing complexity.

In waveguide-based feed networks, two basic antenna types are most often employed. For high gain applications, a waveguide feed horn will typically be used. This may provide both high gain and wide bandwidth (> 15% fractional bandwidth). For wide field-of-view applications, slotted antennas are often used. A slotted antenna formed in an air metal waveguide will exhibit such a bandwidth: which is larger than the bandwidth from the substrate integrated waveguide but smaller than the desired bandwidth (e.g., 2GHz at 79GHz when the desired bandwidth is 4GHz to 5 GHz).

The bandwidth requirements are highly dependent on the application. For doppler radar systems, two main benefits can be derived from a wide bandwidth (e.g., 4Ghz to 5 Ghz): (i) A wide fractional bandwidth can be utilized to provide high range resolution (proportional to the speed of light divided by the bandwidth), i.e., a 4GHz bandwidth will provide a range resolution of 3.5 cm. This is most desirable when the radar is detecting objects in close proximity to the sensor. For example, when performing parking assistance, whether the vehicle is 1 meter or 1.05 meters away is critical information, but when performing adaptive cruise control, whether the vehicle is 200 meters or 200.05 meters away is not important; and (ii) a wide fractional bandwidth may also be used to provide radar systems with the following capabilities: a smaller instantaneous bandwidth (i.e., 500 Mhz) is employed but the frequencies are switched within this wider fractional bandwidth to avoid interference. Corner radars or short range radars are more susceptible to interference from nearby vehicles because they provide a wider angular coverage. Additionally, as the number of vehicles on the road employing corner radars increases, the interference problem also worsens.

In summary, in the field of waveguide feed antennas for radar applications, narrow field of view antennas with large bandwidth can be produced, but large bandwidth is not an important feature due to the radar application. In applications where a large (wide) bandwidth would be important, a narrow field of view of the feedhorns is not desirable. Thus, in the field of waveguide fed radar antennas, there are the following performance gaps: it provides value to the market but currently does not enable a combination of a wide fractional bandwidth (e.g., 4Ghz to 5Ghz at 79 Ghz) with a wide field of view (e.g., 120 degrees half power azimuth beam width) in a cost effective manner.

Rogowski (Rogers Corporation) developed a technique for solving the antenna problem, a dielectric resonator antenna embodiment. The dielectric resonator antenna invented by rogers corporation provides a combination of wide field of view and wide bandwidth as desired for corner radar applications. However, to date, this dielectric resonator antenna has been used with PCB-based substrate integrated waveguide feed networks, which has the problems described above with respect to insertion loss between MMIC and antenna. While it is of course possible and in some cases desirable to combine a dielectric resonator antenna with a waveguide feed network, the increased cost of both systems may prevent their use in some high capacity applications. Thus, there is an unmet need for a waveguide feed wide field of view, wide bandwidth antenna that can be obtained at a competitive price relative to a single waveguide plus slotted antenna.

While the above technical background focuses on automotive radars, it is contemplated that these requirements will shift to a scenario other than automotive applications, for example, a set of radars utilized in a factory automation scenario (at 60 Ghz) may also experience a similar set of challenges.

Regarding waveguide fabrication, there are two main methods for producing waveguides plus antennas for high volume radar applications today: (i) multilayer molding a conventional waveguide; and (ii) a bandgap waveguide. Evaluating the relative benefits of two systems is largely an activity of comparing complexity and thus cost.

Conventional waveguides are formed by: molding a plurality of plastic layers, metallizing the layers, and bonding the layers together with a conductive adhesive or in another manner to provide a consistent and reliable electrical connection from one layer to another. Examples of such stacks can be found in U.S. patent publication 2020/0313304. The complexity in this system arises from the number of metallized plastic layers (up to 7 layers for complex structures and 2 to 3 layers for simple structures) and the need to join the layers together with a strong electrical connection between the layers.

The bandgap waveguide utilizes a specialized structure to form the inner walls of the waveguide. This structure is referred to as an "electromagnetic bandgap structure" or "artificial magnetic conductor". The main benefit of this structure is that a strong electrical connection between the top and bottom of the waveguide is not required in this structure, thus reducing the complexity of the waveguide assembly. This benefit has proven to be of market value.

However, this structure may introduce some additional complexity into the molding tolerance requirements and requires four metal layers in a typical structure. As the number of layers in the structure increases, the complexity of fabrication increases in a non-linear fashion, and the cost of materials increases with the number of metal layers. Accordingly, there is an unmet need in the marketplace for a solution having: (i) A feed network that may be excited from in-package antenna excitation or similar MMIC package excitation; (ii) Providing low insertion loss, for example, 0.25 dB/inch to 0.5 dB/inch at 79 Ghz; (iii) Ability to be manufactured at minimal cost and minimal complexity; (iv) the potential to provide an antenna solution of: the antenna solution provides a wide field of view and a large bandwidth, e.g., a 120 degree half power beamwidth and a 5GHz bandwidth with a center frequency of 78.5 GHz; (v) alternatively, the following system: the system provides the first three points with reduced cost and reduced complexity, and provides high gain and optionally wide bandwidth, which would be desirable for other applications such as long range radar; (vi) A feed network that may be excited from the PCB or form an in-package antenna excitation or similar MMIC excitation; (vii) Low insertion loss, for example 0.25 dB/inch to 0.5 dB/inch at 79 GHz; (viii) The ability to be fabricated with only one metallization layer and potentially one dielectric layer (optionally, only metallized plastic; in preferred embodiments, dielectric); (ix) an antenna providing the following solution: this solution provides a wide field of view and a large bandwidth, e.g., a 120 degree half power beamwidth and a 5GHz bandwidth with a center frequency of 78.5 GHz; and (x) alternatively, a system that can provide high gain and optionally large bandwidth.

Some dielectric resonator antennas may be tailored to a desired pattern over a large bandwidth range, but have large gain losses due to the required feed structure and losses in transitions when incorporated into an antenna system. Some molded conventional waveguide antennas may be incorporated into antenna systems that minimize losses in feed and transition to achieve high gain, but these antenna systems provide less available bandwidth (i.e., < 3 GHz).

While existing antennas may be suitable for their intended purpose, there is still a need for: a pattern customizable high gain antenna system (with minimal feed and transition losses) that can be customized to high gain and controlled antenna pattern shape with respect to angle over a large bandwidth up to the millimeter wave band (i.e.,. Gtoreq.4 GHz).

The following publications may be considered as useful background art: U.S. patent number 3,015,100, U.S. patent number 6,043,787, and U.S. patent publication 2020/0313304.

Disclosure of Invention

Embodiments include an open waveguide antenna as defined in the appended independent claims. Further advantageous modifications of the open waveguide antenna are defined by the appended dependent claims.

Embodiments include a waveguide antenna system having: an electromagnetic EM transition section having a transition region, having a signal feed interface and an open waveguide section, the EM transition section configured to couple EM energy from the signal feed interface to a guided waveguide mode of the EM energy via the transition region to the open waveguide section; and a leaky waveguide antenna portion configured and arranged to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support electromagnetic energy transfer from the signal feed structure to the leaky waveguide antenna portion.

Embodiments include a waveguide antenna system having: a plurality of waveguide antenna systems as disclosed hereinabove configured for on-package antenna applications.

Embodiments include a waveguide antenna system having: a plurality of waveguide antenna systems as disclosed hereinabove configured for use in patch-on-printed circuit board applications.

Embodiments include an open waveguide signal feed system having: a printed circuit board having a signal feed and a signal feed output; an open waveguide having a signal feed input port; a transition region disposed between and in signal communication with the signal feed output and the signal feed input port; wherein the signal feed comprises a microstrip, coplanar waveguide or stripline; wherein the signal feed output comprises a patch or probe.

Embodiments include an open waveguide section having: at least one bend in a slot waveguide, the at least one bend having the following slots in a propagation direction of an electromagnetic wave in the slot waveguide: the trough having opposed first and second side walls, a baffle disposed between the first and second side walls, a first base disposed between the first and baffle, and a second base disposed between the baffle and the second side wall, wherein at least all surfaces of the first, second, baffle, first base, and second base within the trough are electrically conductive; and an electromagnetic radiation inhibitor strategically configured and arranged to: suppressing unwanted electromagnetic radiation that may emanate from at least one bend in the absence of the electromagnetic radiation inhibitor.

Embodiments include an open waveguide antenna having: a trough having opposed first and second side walls, a partition disposed between the first and second side walls, a first base disposed between the first and partition, and a second base disposed between the partition and the second side wall; wherein at least one or more of the surfaces of the first sidewall, the second sidewall, the partition, the first base, and the second base inside the slot are electrically conductive; wherein the first base has a first sequence of undulations longitudinally disposed along the length of the trough; wherein the undulations of the first sequence alternately and sequentially follow a first curved path and a second curved path, the second curved path being asymmetric with the first curved path; wherein the second base has a second sequence of undulations longitudinally disposed along the length of the trough; wherein the undulations of the second sequence alternately and sequentially follow the second curved path and the first curved path; wherein the first and second curved paths alternate along the length of the slot from one side of the separator to the other side of the separator.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Drawings

Referring to the exemplary, non-limiting drawings wherein like elements are numbered or shown similarly:

Respectively, fig. 1A depicts a cross-sectional end view of an example slot waveguide according to an embodiment, fig. 1B depicts a cross-sectional end view of an example slot waveguide antenna according to an embodiment, and fig. 1C depicts a transparent cross-sectional side view of an example slot waveguide antenna of fig. 1B according to an embodiment;

FIG. 2 depicts a rotated isometric transparent view of the example slot waveguide antenna of FIGS. 1B and 1C, according to an embodiment;

FIG. 3 depicts analytically modeled performance characteristics of the example slot waveguide antenna of FIG. 2, according to an embodiment;

Fig. 4A, 4B and 4C depict views similar to those of fig. 1A, 1B and 1C, respectively, but with a dielectric cover on top of the example slot waveguide and the example slot waveguide antenna, according to an embodiment;

fig. 5 depicts a rotated isometric transparent view of the example slot waveguide antenna of fig. 4B and 4C, according to an embodiment;

FIG. 6 depicts analytically modeled performance characteristics of the example slot waveguide antenna of FIG. 5, according to an embodiment;

Fig. 7A depicts a cross-sectional end view of the example slot waveguide antenna of fig. 1B and 1C with a signal feed, and fig. 7B depicts a cross-sectional side view of the example slot waveguide antenna of fig. 1B and 1C with a signal feed, respectively, according to an embodiment;

Fig. 8A depicts a top plan view of the single and multiple example slot waveguide antennas of fig. 2 or 5, respectively, according to an embodiment, fig. 8B depicts a repeated top plan view of the single and multiple example slot waveguide antennas of fig. 2 or 5, according to an embodiment, and fig. 8C depicts a final top plan view of the single and multiple example slot waveguide antennas of fig. 2 or 5, according to an embodiment;

FIG. 9 depicts analytically modeled performance characteristics of the embodiment of FIG. 8C, according to an embodiment;

Fig. 10A depicts a rotated isometric top view of a slot waveguide antenna having features that facilitate its manufacturability according to an embodiment, and fig. 10B depicts a rotated isometric bottom view of a slot waveguide antenna having features that facilitate its manufacturability according to an embodiment;

FIG. 11 depicts a conceptual top plan view, i.e., the x-y plane, of an on-package antenna feed with transitions and having transmit slot waveguide antennas and receive slot waveguide antennas, according to an embodiment;

fig. 12 depicts a conceptual end view, i.e., the y-z plane, of the on-package antenna feed of fig. 11, according to an embodiment;

fig. 13 depicts a conceptual side view, i.e., the x-z plane, of the on-package antenna feed of fig. 11, according to an embodiment;

Fig. 14A depicts a transparent side view of an example first transition in the form of a ridge waveguide transitioning to a slot waveguide antenna according to an embodiment, fig. 14B depicts an end view of the first transition of fig. 14A according to an embodiment, and fig. 14C depicts an EM performance characteristic of the embodiment of fig. 14A according to an embodiment;

Fig. 15A depicts a transparent rotational isometric view of an example second transition disposed between a rectangular waveguide and a slot waveguide antenna, and fig. 15B depicts EM performance characteristics of the embodiment of fig. 15A, according to an embodiment;

FIG. 16A depicts a top-down block diagram of an example third transition in the form of a waveguide bend, and FIG. 16B depicts an EM performance characteristic of the embodiment of FIG. 16A, according to an embodiment;

Fig. 17A depicts a transparent side view of an example fourth transition in the form of a rectangular waveguide according to an embodiment, and fig. 17B depicts a top plan view of the embodiment of fig. 17A according to an embodiment; and FIG. 17C depicts EM performance characteristics of the embodiments of FIGS. 17A and 17B, according to an embodiment;

Fig. 18 depicts a block diagram side view of an example conceptual illustration of a patch, transition waveguide with bend and transition loss, slot waveguide with loss, and slot waveguide antenna according to an embodiment;

FIG. 19 depicts analytical modeling results of slot waveguide loss according to an embodiment;

FIGS. 20A and 20B depict example top block diagram plan views of conceptual models for controlling radiation from dielectric discontinuities of a slot waveguide antenna, according to an embodiment;

respectively, fig. 21A depicts a rotational isometric transparent view of a first patch-to-slot waveguide transition in which patch E polarization is parallel to a baffle according to an embodiment, fig. 21B depicts a top transparent plan view of a first patch-to-slot waveguide transition in which patch E polarization is parallel to a baffle according to an embodiment, and fig. 21C depicts a transparent side view of a first patch-to-slot waveguide transition in which patch E polarization is parallel to a baffle according to an embodiment;

22A, 22B and 22C depict, in various levels of detail, a rotated isometric transparent view of a second patch-to-slot waveguide transition in which the patch E polarization is perpendicular to the baffle, in accordance with an embodiment;

FIG. 23 depicts performance characteristics of the patch-to-slot waveguide transition depicted in FIGS. 21A-21C, according to an embodiment;

FIG. 24 depicts an example waveguide antenna system having an open waveguide and leaky waveguide antenna and configured for antenna-on-package applications, according to an embodiment;

FIGS. 25A and 25B depict block diagram representations of the basic differences between the open waveguide (FIG. 25A) and leaky waveguide antenna (FIG. 25B) of the system of FIG. 24, in accordance with an embodiment;

FIG. 26 depicts a method with a given propagation constant, according to an embodiment Is a sample guided wave;

fig. 27 depicts a trench waveguide as an example of an open-type waveguide according to an embodiment;

Fig. 28A depicts a top view of an open trench waveguide and leaky waveguide antenna according to an embodiment, fig. 28B depicts a front transparent view of an open trench waveguide and leaky waveguide antenna according to an embodiment, and fig. 28C depicts a side transparent view of an open trench waveguide and leaky waveguide antenna according to an embodiment, respectively;

fig. 29 depicts radiation performance characteristics of the open trench waveguide leaky-wave antenna of fig. 28A according to an embodiment;

Fig. 30 depicts a block diagram top plan view of an example transition region between an electromagnetic transmission line and an open waveguide, according to an embodiment;

FIG. 31 depicts a block diagram side view of another example transition region between an electromagnetic transmission line and an open waveguide, according to an embodiment;

fig. 32A depicts a rotated isometric transparent view of an open waveguide bend according to an embodiment, and fig. 32B depicts a top plan view of an open waveguide bend according to an embodiment, and fig. 32C and 32D depict the relevant electromagnetic performance characteristics of fig. 32A and 33B according to an embodiment;

FIG. 33 depicts a block diagram cross-sectional longitudinal view through a bend in a dual channel open waveguide with an electromagnetic radiation absorber, according to an embodiment;

34A and 34B depict block diagram cross-sectional longitudinal views through two versions of a bend in a dual channel open waveguide with electromagnetic radiation chokes (quarter wave channels), according to an embodiment;

Fig. 35A, 35B and 35C depict block-diagram cross-sectional longitudinal views through three versions of bends in a single-channel open waveguide with an electromagnetic radiation choke as an alternative to the electromagnetic radiation choke depicted in fig. 34A and 34B, according to an embodiment;

FIG. 36A depicts a rotational isometric transparent view of an open waveguide bend with a modified septum within the bend, and FIG. 36B depicts a transparent side view of an open waveguide bend with a modified septum within the bend, and FIGS. 36C and 36D depict the relevant electromagnetic performance characteristics of FIGS. 36A and 36B, according to an embodiment;

FIG. 37A depicts a rotational isometric transparent view of an open waveguide bend with a modified floor structure within the bend, and FIG. 37B depicts a top plan view of an open waveguide bend with a modified floor structure within the bend, and FIGS. 37C and 37D depict related electromagnetic performance characteristics of FIGS. 37A and 37B, according to an embodiment;

FIG. 38 depicts a block diagram cross-sectional longitudinal view of a bend through an open waveguide with a modified waveguide structure within the bend, according to an embodiment;

FIG. 39A depicts a rotational isometric transparent view of an open waveguide bend with a modified wall structure within the bend, and FIG. 39B depicts a top plan view of an open waveguide bend with a modified wall structure within the bend, and FIGS. 39C and 39D depict the relevant electromagnetic performance characteristics of FIGS. 39A and 39B, according to an embodiment; and

Fig. 40A depicts a block-diagram cross-sectional longitudinal view through a bend of an open waveguide, fig. 40B depicts a modified version of fig. 40A with increased inductance within the bend, fig. 40C depicts a modified version of fig. 40A with increased capacitance within the bend, and fig. 40D and 40E depict related electromagnetic performance characteristics of fig. 40B and 40C, respectively, according to an embodiment.

Those skilled in the art will appreciate that the figures described further below are for illustration purposes only. It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions or scale of some of the elements may be exaggerated relative to other elements for clarity. Furthermore, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements, or similar elements may not be repeated among all of the figures, wherein it is to be appreciated and understood that such recitation is not inherently disclosed.

Detailed Description

As used herein, the phrase "embodiments" means "embodiments disclosed and/or illustrated herein," which may not necessarily include specific embodiments of the invention according to the appended claims, but are nonetheless provided herein as being useful for a complete understanding of the invention according to the appended claims.

Although the following detailed description contains many specifics for the purpose of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the appended claims. For example, where features described may not be mutually exclusive, and where features described are not mutually exclusive with respect to other described features, combinations of such non-mutually exclusive features are considered inherently disclosed herein. Additionally, common features may be shown in common in various figures, but for simplicity may not be specifically recited in all figures, but are recognized by those skilled in the art as explicitly disclosed features even though such features may not be recited in a particular figure. Accordingly, the following example embodiments are set forth without loss of generality to, and without imposing limitations upon, the claimed invention disclosed herein.

The embodiments as shown and described by the various figures and accompanying text provide an antenna system that can be tuned from patch feeding (i.e., patch feeding on an in-package antenna or circuit board structure) through transitions to an open waveguide antenna structure with minimal loss of the overall structure, thereby achieving a customizable high gain antenna system that can be used over large bandwidths (i.e.,. Gtoreq.4 GHz) and up to millimeter wave frequencies.

For simplicity of integration and description herein, the feed structure used may be a patch, but other feed structures such as probes (e.g., coaxial wires, plated holes in printed circuit boards, etc.), loops, or apertures are also possible and contemplated herein. The patch structure may desirably be part of an antenna chip in a package to minimize distance, achieve miniaturization, and reduce cost by avoiding additional RF layers. However, the patch may also be formed on any type of substrate layer, including build-up layers or layers in a printed circuit board.

The open waveguide antenna may be specifically designed to achieve a desired antenna radiation pattern. For example, a wide field of view may be obtained, which is often useful in corner radar applications for automotive safety systems. In other cases, such as in forward facing long range automotive radar applications, it may be desirable to achieve maximum gain over a narrower field of view. Variables of the open waveguide antenna that can be adjusted to achieve a desired pattern can include: the size of the open radiation aperture, the angle of the radiation aperture, the basal plane relief or the dielectric discontinuity that produces the radiation. Furthermore, a dielectric cap or lens structure may be added over the metal open waveguide to further optimize the pattern. In the case where multiple antenna channels are required, such as in the corner radar applications described above, multiple open waveguide antenna structures may be combined into one piece for ease of manufacture, with individual open waveguide antenna elements separated by a distance of 0.5 to 10 times the wavelength of the signal being processed.

Various features that facilitate manufacturing while maintaining equally excellent RF performance may be included in the open waveguide antenna design. These features include: component "shelling" for reducing material consumption and warpage, recess and positive features for avoiding sticking during metallization or other processing by electroplating, and draft angle and convenient parting line location for facilitating component removal.

The fabrication methods for producing single or multi-channel open waveguide antenna structures can be accomplished by a variety of methods including metal die casting, surface metallization after injection molding of dielectrics, and singulation and surface metallization after extrusion.

The transition from the feed structure to the open waveguide antenna is designed to minimize losses. Suitable transition structures for achieving this include: a ridge waveguide with patch feeding, a rectangular waveguide with patch feeding, an open waveguide with patch feeding or probe feeding, a coplanar waveguide, etc.

Another embodiment as shown and described by the various figures and accompanying text provides a slot waveguide antenna (TWGA) that is useful in one example for automotive radar applications. TWGA combine the functionality of a slot waveguide with the functionality of an Electromagnetic (EM) radiator (antenna). The slot waveguide has symmetry between the left and right sides of its dividing partition and operates primarily as a guided mode EM transmission element. In contrast, slot waveguide antennas have asymmetry between the left and right sides of their dividing partition walls and necessarily have at least partially open tops, which enables them to operate as both EM transmitting and EM radiating elements. As used herein, the phrase "open top" means TWGA top, cover, or ceiling that is open to or allows passage of EM radiation energy. Thus, the presence of a dielectric cap over TWGA is not precluded by the open top. A Monolithic Microwave Integrated Circuit (MMIC) may be used to introduce signals into the input ports of TWGA.

Although reference is made herein to slot waveguide antennas, it should be understood that the more general terms used to describe slot waveguide antennas refer to open waveguide antennas, where the slot waveguide antennas described above are a specific subset of the open waveguide antenna structure.

As used herein, the term "monolithic" means a structure integrally formed from a single material composition.

While the embodiments shown and described herein depict example TWGA having a particular three-dimensional (3D) geometry, it should be understood that this geometry is merely one example of many geometries that may be employed in a TWGA design according to the desired performance characteristics of TWGA (operating frequency, bandwidth, gain, return loss, radiation pattern, etc.). It should also be appreciated that modifications to the disclosed geometries may be made without departing from the scope of the invention. Accordingly, the disclosure herein is applicable to any TWGA designs that fall within the scope of the appended claims, and any 3D geometry that falls within the scope of the disclosure herein and is suitable for the purposes disclosed herein is contemplated and considered as a complement to the specific embodiments disclosed herein.

Reference is now made to fig. 1A-10B in connection with an example open waveguide antenna, and in particular in connection with an example open slot waveguide antenna in general.

Fig. 1A depicts a cross-sectional end view of an example open slot waveguide (TWG) 1000, fig. 1B depicts a cross-sectional end view of an example open slot waveguide antenna (TWGA) 2000, and fig. 1C depicts a transparent cross-sectional side view of an example TWGA 2000 of fig. 1B, respectively. It can be seen that TWGA has similar structural characteristics as TWG 1000, but has structural differences that point to the asymmetry of the left and right bases and the undulations present in the left and right bases on either side of the separator of TWGA 2000.

In an embodiment, the TWG 1000 (more generally referred to herein as an open waveguide) has: a slot 1010 having opposing first and second side walls 1020, 1030, a partition 1040 disposed between the first and second side walls 1020, 1030, a first base 1050 disposed between the first and partition 1020, 1040, and a second base 1060 disposed between the partition 1040 and the second side wall 1030; wherein at least all of the surfaces 1070 of the first side wall 1020, the second side wall 1030, the spacer 1040, the first base 1050, and the second base 1060 within the slot 1010 are electrically conductive. In an embodiment, as viewed from the perspective of fig. 1A, the partition 1040 extends upward from the first base 1050 and the second base 1060. In an embodiment, TWG 1000 has a monolithic 3D dielectric construction and has the conductive surface 1070 described above disposed thereon. In an embodiment, the first base 1050 and the second base 1060 are electrically conductive at all surfaces inside the slot 1010. In an embodiment, conductive surface 1070 is deposition coated with a conductive material. For purposes disclosed herein, as used herein and with respect to the conductive surface of at least TWG 1000 (also referred to herein as an open waveguide section), the phrase "conductive" means conductive at the operating frequency of interest, which may include surfaces that are non-conductive in the DC sense but sufficiently conductive at the operating frequency of interest in the AC sense.

In an embodiment TWGA 2000 (more generally referred to herein as an open waveguide antenna) has: a trough 2010 having opposed first and second side walls 2020, 2030, a partition 2040 disposed between the first and second side walls 2020, 2030, a first base 2050 disposed between the first and partition 2020, 2040, and a second base 2060 disposed between the partition 2040 and the second side wall 2030; wherein at least all surfaces 2070 of the first sidewall 2020, the second sidewall 2030, the spacer 2040, the first base 2050, and the second base 2060 inside the slot 2010 are electrically conductive; wherein the first base 2050 has a first sequence of undulations 2052 longitudinally disposed along the length of the slot 2010; wherein the undulations 2052 of the first sequence alternating from high to low (left to right in fig. 1C) alternately (high to low in fig. 1C) and sequentially (left to right in fig. 1C) follow a first curved path 2011 and then a second curved path 2012, the second curved path 2012 being asymmetric with the first curved path 2011; wherein the second base 2060 has a second sequence of undulations 2062 disposed longitudinally along the length of the slot 2010; wherein the undulations 2062 of the second sequence that alternate from low to high (left to right in fig. 1C) alternately and sequentially follow the second curved path 2012 and then the first curved path 2011; and wherein the first curved path 2011 and the second curved path 2012 alternate along the length of the slot 2010 from one side of the baffle 2040 to the other side of the baffle 2040 (best seen with reference to fig. 2), but are shown as continuous splines from left to right in the transparent side view of fig. 1C. In an embodiment, the first sequence of undulations 2052 and the second sequence of undulations 2062 are asymmetric about the baffle 2040.

In an embodiment, as seen from the perspective of fig. 1B-1C, a baffle 2040 extends upwardly from the first base 2050 and the second base 2060. In an embodiment TWGA 2000 has a monolithic 3D dielectric construction and has formed or disposed thereon the conductive surface described above. In an embodiment, conductive surface 2070 is deposition coated with a conductive material.

In an embodiment, at least a portion of the first sequence of undulations 2052 comprises a dielectric material and/or at least a portion of the second sequence of undulations 2062 comprises a dielectric material. Radiation control of the leakage TWGA, 2000 may be further achieved by strategically placing the dielectric material as part of the undulations 2052, 2062.

As depicted in fig. 1A, TWG 1000 has an overall waveguide height Hg relative to outer base surface 500, a base height Hb relative to outer base surface 500, a sidewall height Hw relative to Hb, and a bulkhead height Hs relative to first base 1050 or second base 1060. In an embodiment, hg is equal to the sum of Hb and Hw. In an embodiment, hs is less than Hw.

Fig. 2 depicts a rotated isometric transparent view of example TWGA 2000 of fig. 1B and 1C. In an embodiment, TWGA 2000 is fed via signal port 2400 on one end 2100 (first end) of TWGA 2000 by a slot waveguide mode. The opposite second end 2200 (second end) of TWGA 2000 has a conductive shorting circuit 2500, which conductive shorting circuit 2500 is electrically connected to a conductive surface 2600 provided at the upper end 2300 of TWGA 2000. In fig. 2, the undulations visible in the first sequence of undulations 2052 and the second sequence of undulations 2062 are depicted for comparison with the undulations in fig. 1C.

From the foregoing discussion and description of fig. 1B-1C and fig. 2, it should be understood that the embodiments disclosed herein include the following: which may or may not be a variation of the configuration of TWGA 2000 depicted in fig. 1B-1C and 2. In an embodiment, the exposed surfaces of the first sidewall 2020, the second sidewall 2030, and the spacer 2040 are non-parallel to each other along the length of the groove 2010, which when combined with an appropriate draft angle provides support for manufacturing TWGA 2000 via a molding technique. In an embodiment, as depicted in at least fig. 1B and 1C, the height of the spacer 2040 is less than the height of the first sidewall 2020 or the second sidewall 2030. In an embodiment, the spacer 2040 is disposed centrally between the first and second sidewalls 2020, 2030, however, it is understood that variations of this configuration are possible in accordance with other embodiments disclosed herein. In an embodiment, the first sequence of undulations 2052 alternate between a first curved path 2011 and a second curved path 2012 along the length of the slot 2010 at high Cheng Fangmian (left to right as viewed in fig. 1C), and the second sequence of undulations 2062 alternate between the second curved path 2012 and the first curved path 2011 along the length of the slot 2010 at high Cheng Fangmian (left to right as viewed in fig. 1C). In an embodiment and as viewed in the side view of fig. 1C, the first curved path 2011 of the slot 2010 is a first waveform (also referred to herein by reference numeral 2011) having alternating peaks and valleys, the first waveform 2011 being a composite of a first smooth waveform multiplied by a first square wave. Similarly, the second curved path 2012 of the groove 2010 is a second waveform (also referred to herein by reference numeral 2012) having alternating peaks and valleys, the second waveform 2012 being a composite of the second smooth waveform multiplied by the second square wave. In an embodiment, the second smooth waveform and the first smooth waveform have different elevations in both the peaks and the valleys between the first end 2100 and the second end 2200 of the slot 2010 and at all points inside the first end 2100 and the second end 2200.

Fig. 3 depicts analytically modeled performance characteristics of the example TWGA 2000 of fig. 1B, 1C, and 2. The depicted analytical data is taken at a point P that is sufficiently far from TWGA to be considered in the far field. As depicted, the embodiment of TWGA 2000 is configured to: with a line of sight (θ=0) that achieves a gain of about 12dBi, and with specific sidelobe gain peaks and radiation patterns in the azimuth (Φ=0) plane and the elevation (Φ=90) plane (compare to fig. 6).

Referring now to fig. 4A, 4B, 4C, 5, and 6, wherein fig. 4A, 4B, and 4C depict views similar to the views of fig. 1A, 1B, and 1C, respectively, but with a dielectric Dk cover 3000 (also referred to herein as a lens or cover) on top of the example TWG 1000 and the example TWGA 2000. Fig. 5 depicts a rotated isometric transparent view of TWGA of fig. 4C, which TWGA 2000 is similar to TWGA in fig. 2 but with a cover 3000, and fig. 6 depicts an analytically modeled performance characteristic of an example slot waveguide antenna 2000 with a cover 3000 as depicted in fig. 5, which is similar to the performance characteristic of fig. 3. When generally discussed, the Dk cover is referred to herein by reference numeral 3000; when discussed with respect to TWG 1000, dk cover is referred to herein by reference numeral 3100; and when discussed with respect to TWGA 2000, dk cover is referred to herein by reference numeral 3200. As depicted, dielectric cap 3200 is disposed at and extends over the top of slot 2010 of TWGA at a width Wc equal to or greater than the width Wt of the upper open end of slot 2010. The thickness, width, and general shape of the dielectric cover 3100 over TWGA 2000 are used to control the azimuth and elevation EM radiation patterns and shapes emanating from TWGA 2000. As an example, the covers 3100 and/or 3200 may include surface discontinuities 3010, such as dimples, or protrusions (not shown) depicted in fig. 4A and 4B, for control of the azimuthal EM radiation pattern and shape described above. Dielectric cap 3200 also provides additional degrees of freedom in the design of such an antenna that complements the overall performance of the antenna. It is contemplated that such performance improvement may be embodied in improved return loss, improved sidelobe levels, and/or any other antenna output characteristics that would be so affected. In an embodiment, the dielectric cap 3000 has a dielectric constant greater than 1 and equal to or less than 13.

Fig. 5 depicts a rotated isometric transparent view of example TWGA 2000 of fig. 4B and 4C. Similar to the embodiment of fig. 2, TWGA 2000 of fig. 5 is fed through signal port 2400 on one end 2100 of TWGA 2000 by a slot waveguide mode. The opposite end 2200 of TWGA 2000 has a conductive shorting circuit 2500, which conductive shorting circuit 2500 is electrically connected to a conductive surface 2600 provided at the upper end 2300 of TWGA 2000.

Fig. 6 depicts analytically modeled performance characteristics of the example TWGA with cap 3200 of fig. 5. The measurement shown is taken at a point P that is sufficiently far from TWGA a and the lid 3200 to be considered in the far field. As depicted, the embodiment TWGA with the lid 3200 is configured to: with a line of sight (θ=0) that achieves a gain of about 12dBi, and with specific sidelobe gain peaks and radiation patterns in the azimuth (Φ=0) plane and the elevation (Φ=90) plane (compare to fig. 3). As can be seen by comparing the sidelobe gain peaks and radiation patterns of fig. 3 and 6, it can be seen that the presence of Dk cover 3200 has a greater effect on the shape and distribution of EM radiation in the sidelobes than on the boresight gain. It can also be observed that Dk cap 3200 increases the azimuthal radiation gain (phi=0) over a larger angular spread.

Fig. 7A depicts a cross-sectional end view of the example TWGA 2000 of fig. 1B and 1C, and fig. 7B depicts a cross-sectional side view of the example TWGA 2000 of fig. 1B and 1C, respectively, with the signal feed 4000 disposed in signal communication with the signal port 2400 at the first end 2100 of TWGA 2000.

Fig. 8A depicts top plan views of single and multiple examples TWGA in fig. 2 or 5, respectively, fig. 8B depicts repeated top plan views of single and multiple examples TWGA 2000 in fig. 2 or 5, and fig. 8C depicts final top plan views of single and multiple examples TWGA 2000 in fig. 2 or 5, wherein the assembled multiple TWGA 2000 (fig. 8C) form a multichannel TWGA 2700.

Fig. 9 depicts an analytically simulated performance characteristic of the embodiment of fig. 8C as a separate one of the multiple channels TWGA 2700. As can be seen by comparing the analysis diagram of fig. 9 with the analysis diagram of fig. 3, the multi-channel TWGA 2700 produces a similar gain curve as seen at phi=90 and produces a flatter gain curve as seen at phi=0. The TWGA profile in combination with the dielectric cover enables the multi-channel antenna pattern to have a variety of shapes.

Fig. 10A depicts a rotated isometric top view of example TWGA 2000 with feature 5000 and fig. 10B depicts a rotated isometric bottom view of example TWGA 2000 with feature 5000, the feature 5000 contributing to its manufacturability without seriously compromising electromagnetic performance. For example, manufacturability features 5000 can include one or more of the following: (i) The positive protrusion makes features 5010, which do not allow flat surfaces or flat surface features to stick during the barrel plating process (i.e., positive features interrupt successive flat planes); (ii) Screw locations 5020, which incorporate or not incorporate grooves (as shown) for receiving flat head screws or similar fasteners; (iii) Rib features 5030 for reducing material consumption and warpage; (iv) Recessed features 5040 for reducing sticking tendency during electroplating; (v) A molded draft angle feature 5050 disposed on the top side/surface of the TWGA 2000 monolithic 3D dielectric structure that is equal to or greater than 2 degrees; (vi) A molded draft angle feature 5060 disposed on the bottom side/surface of the TWGA 2000 single 3D dielectric structure that is equal to or greater than 4 degrees; and (vii) a molded parting line feature 5070 placed near the bottom surface of the TWGA a single 3D dielectric structure. While specific draft angles, such as 2 degrees and 4 degrees, for example, are set forth above, it should be understood that these draft angles are merely example draft angles that may be suitable for a particular purpose and surface, are not intended to limit the invention disclosed herein in any way, and may include any draft angle suitable for a manufacturing process that may include uniaxial molding.

Reference is now made to fig. 11-23B, which generally relate to an example TWGA system having at least one TWGA 2000,2000.

Fig. 11 depicts a conceptual top view, i.e., the x-y plane, of TWGA system 6000, the TWGA system 6000 having: an on-package antenna (AoP) feed 6100 on the bottom package 6050; electromagnetically coupled waveguide transition (alternatively referred to herein as transition region) 6200; and transmit antenna 2800 and receive antenna 2850, each in the form of TWGA a 2000, respectively, are electromagnetically coupled to waveguide transition 6200. In an embodiment, aoP feed 6100 includes patch antenna 6150 disposed on bottom package 6050. In an embodiment, aoP feed 6100 and/or patch antenna 6150 have the form of a planar signal feed structure.

Fig. 12 depicts a conceptual end view, i.e., y-z plane, of the TWGA system 6000 of fig. 11, the TWGA system 6000 having: aoP feeds 6100, waveguide transitions (transition regions) 6200, and transmit antennas 2800 and receive antennas 2850 on the bottom package 6050. Here, dk cap 3000 is also depicted above TWGA 2800 and TWGA 2950. Solder ball connectors 6060 for electrically connecting TWGA system 6000 to an underlying PCB (printed circuit board) (not shown) are also depicted, as well as an integrated RFIC (radio frequency integrated circuit) chip 6070. As depicted, a waveguide signal feed interface 6205 is disposed between AoP feed 6100 and waveguide transition 6200 to form a portion of electromagnetic EM transition 100. In an embodiment, each EM transition section 100 is configured to couple EM energy from the signal feed interface 6205 to the guided waveguide mode of EM energy to the open waveguide section 1000 via the transition region 6200, according to an embodiment of the structure disclosed hereinafter. In an embodiment, the waveguide signal feed interface 6205 includes a waveguide input port of the waveguide transition 6200. AoP feed 6100, or any of the signal feeds disclosed herein, in combination with waveguide signal feed interface 6205, or any of the signal feed interfaces disclosed herein, may be considered as an area where EM signals are launched into EM transition 100.

Fig. 13 depicts a conceptual side view, i.e., the x-z plane, of the TWGA system 6000 of fig. 11, the TWGA system 6000 having: aoP feeds 6100, waveguide transitions 6200, transmit and receive antennas 2800, 2850, and Dk cover 3000 over TWGA 2800, TWGA 2850 in left and right configurations on the bottom package 6050.

Fig. 14A depicts a transparent side view of an example first transition region 6210 (generally represented by reference numeral 6200) in the form of a ridge waveguide 1100 transitioning (from left to right) to TWGA 2000; FIG. 14B depicts an end view of the first transition of FIG. 14A; and FIG. 14C depicts the EM performance characteristics of the embodiment of FIG. 14A. Here, aoP feed 6100 is centered between the lower ridge (see h 1) and the upper ridge (see h 3), and the first transition 6210 is similar to TWG 1000 described above, but with a septum 1041 similar to septum 1040 described above, wherein septum 1041 slopes upward from port 1 6300 (an analysis port for analytical modeling) on the left side of first transition 6210 to TWGA 2000 on the right side of first transition 6210, wherein the overall height of septum 1041 varies from h1 to h2 relative to base 500, wherein in this example, h2 is greater than h1. In an embodiment, H1 is also greater than H2. As depicted, the height of the partition 1041 increases from port 1 6300 to TWGA 2000, with h2+h2 being greater than h1+h1. As depicted and similar to fig. 12, the signal feed interface 6205 is disposed between AoP feed 6100 and first transition region 6210 to form a portion of the EM transition 100, which EM transition 100 also includes a ridge waveguide 1100. As depicted, port 2 6400 (an analysis port for analysis modeling) is depicted as being located on the right side of TWGA 2000. Port 1 6300 and port 2 6400 are used herein for analysis purposes to analyze S matrix network parameters S11 and S21 as depicted in the S matrix diagram (dB) of fig. 14, which indicates a low EM reflection S11 from input port 6300 and a high EM transmission S21 between input port 6300 and output port 6400, both of which are desired performance characteristics of the embodiments disclosed herein. As depicted, favorable return loss S11 and EM transmissions S21 are observed at frequencies at or above 75 GHz.

With further reference to fig. 14A, the functional dependence of the spacer height (i.e., (H1, H1)) pair relative to the (H2, H2) pair may be linear or quadratic depending on the relative values of the (H1, H1) pair and the (H2, H2) pair.

Fig. 15A depicts a transparent rotational isometric view of an example second transition 6220 disposed between rectangular waveguides 900 and TWGA 2000, and fig. 15B depicts EM performance characteristics of the embodiment of fig. 15A. As depicted, the second transition 6220 in fig. 15 is similar in structure to the first transition 6210 described above in fig. 14, and is also in the form of a ridge waveguide 1200, but with the following differences. Here, the second transition 6220 has a septum 1042 similar to the septum 1041 described above, but where the septum 1042 slopes upward from a height H1 (see, e.g., fig. 14) equal to zero at the rectangular waveguide 900 (as depicted in fig. 15) to a height H2 at TWGA 2000 (as depicted in fig. 15). Another difference between the second transition 6220 and the first transition 6210 is that the first base 105 and the second base 1060 are not sloped. Similar to the embodiment of fig. 14, fig. 15 depicts: port 1 6300 and port 2 6400, used herein for analysis purposes to analyze return losses S11 and S21 as depicted in the S matrix diagram (dB) of fig. 15, which indicates low EM reflection S11 from input port 6300 and high EM transmission S21 between input port 6300 and output port 6400, both of which are desired performance characteristics of the embodiments disclosed herein. As depicted, favorable return loss S11 and EM transmissions S21 are observed at frequencies at or above 60 GHz.

Reference is now made to fig. 16A-23B, which illustrate various embodiments of transitions consistent with embodiments disclosed herein.

Fig. 16A depicts a top block diagram view of an example third transition 6230, the example third transition 6230 being in the form of a waveguide having a 90 degree bend 6202 between an input port 1 6300 and an output port 2 6400; and FIG. 16B depicts the EM performance characteristics of the embodiment of FIG. 16A. As depicted, favorable return loss S11 and EM transmissions S21 were observed at about 80 GHz.

Fig. 17A depicts a transparent side view of an example fourth transition 6240 in the form of a rectangular waveguide, the example fourth transition 6240 being disposed between patches 6150 and TWGA 2000 (not shown), wherein in an embodiment, patch 6150 is disposed on package 6050 to provide AoP feed 6100; FIG. 17B depicts a top plan view of the embodiment of FIG. 17A; and FIG. 17C depicts the EM performance characteristics of the embodiments of FIGS. 17A and 17B. As depicted, favorable return loss S11 and EM transmissions S21 were observed at about 79 GHz.

Fig. 18 depicts a block diagram side view of an example conceptual system 6000, the example conceptual system 6000 having: the patch 6150 disposed on the bottom package 6050, the waveguide transition region 6200 having a bend 6202 and a transition loss analytically estimated to be 0.7dB, the TWG 1000 having a loss analytically estimated to be 0.1 dB/inch, and the radiating element in the form TWGA, all electromagnetically coupled to each other. As depicted and similar to other embodiments disclosed herein, a signal feed interface 6205 is provided between the patch 6150 and the waveguide transition region 6200 to form part of the electromagnetic EM transition portion 100. In an embodiment, each EM transition section 100 is configured to couple EM energy from signal feed interface 6205 to a guided waveguide mode of EM energy to TWG 1000 via transition region 6200 and then direct electromagnetic energy to TWGA 2000.

FIG. 19 depicts example analytical modeling results of (S21) transmission loss versus frequency for an example 1/2 inch long TWG 1000. Fig. 19 shows (S21) dependence of transmission loss on metal conductivity. Al is aluminum, and the different curves represent (S21) transmission loss reduction for different metals (i.e., conductivity relative to aluminum).

Fig. 20A and 20B depict example top view block diagram plan views of conceptual models for controlling radiation from a dielectric discontinuity of TWGA 2000, the TWGA 2000 having bases 2050, 2060 separated by a baffle 2040, wherein the bases 2050, 2060 may or may not have curved paths 2011, 2012 having undulations 2052, 2062, but they do include discrete dielectric radiating elements 2001, 2002 having varying dielectric constants along the direction of EM wave propagation. Comparing the embodiments of fig. 20A and 20B, each radiating element 2001, 2002 may be separated by air to provide individual radiating elements (fig. 20A), or may be joined via an intermediate dielectric medium 2003 (see detail 20.1) to provide a single unified construction (fig. 20B), as depicted in detail 20.1, the individual radiating elements 2001, 2002 may be composed of different dielectric constants whose Dk values vary in the direction of EM wave propagation, and in embodiments may vary according to the pattern of dielectric constant values: dk1-Dk2-Dk3-Dk2-Dk1. In an embodiment, dk1< Dk2< Dk3, however, the Dk values need not follow an ascending or descending order, so long as there is a contrast between adjacent ones of the discrete Dk values. As depicted in detail 20.2, the intermediate dielectric 2003 has a dielectric constant value Dk4 that is different in contrast to Dk1 through Dk 3. In an embodiment, dk4 is significantly less than any of Dk1, dk2, and Dk3, wherein the difference in dielectric constant between Dk4 and any of Dk1, dk2, or Dk3 is at least 3.

Fig. 21A depicts a rotated isometric transparent view of a first patch to slot waveguide transition 6255, fig. 21B depicts a transparent top view of the first patch to slot waveguide transition 6255, and fig. 21C depicts a transparent side view of the first patch to slot waveguide transition 6255, wherein the E-polarization (of patch 6150) is parallel to baffle 1040, and wherein a ridge waveguide 6256 is disposed between patch 6150 and slot waveguide 6257, which in combination form the first patch to slot waveguide transition 6255. Here, the slot waveguide 6257 includes a bend 6258, which bend 6258 does not radiate EM energy as long as symmetry along the slot waveguide cross-section is maintained and the profile of the baffle 1040 across the bend maintains a constant wave impedance along the bend (which may be achieved according to embodiments of the structures disclosed herein). Fig. 21A also depicts an input port 6300 and an output port 6400 that are used for analytical modeling purposes to establish the performance characteristics depicted in fig. 23 discussed below. In the embodiment of fig. 21A, the patch 6150 is fed by a microstrip line (generally indicated by reference numeral 4000) from the side of the waveguide that is marginal to the patch 6150 and in line with the baffle 1040, producing the desired E-polarization parallel to the baffle 1040. An appropriate electrical gap is provided to enable the microstrip to connect with the patch 6150 without shorting, and wherein the impedance of the stripline is the same as and matches the feed line. Alternatively, the patch 6150 of fig. 21A may also be fed from below by a coaxial port without substantial changes to the design. As depicted in fig. 21C and similar to other embodiments disclosed herein, a signal feed interface 6205 is provided between the patch 6150 and the ridge waveguide 6256 to form part of an electromagnetic EM transition 100, the EM transition 100 further comprising a ridge waveguide 6257. In an embodiment, each EM transition section 100 is configured to: EM energy from the signal feed interface 6205 is coupled to a guided waveguide mode of EM energy, reaches the slot waveguide 6257 via the ridge waveguide 6257, and then directs electromagnetic energy to TWGA 2000 (not specifically shown in fig. 21C).

Fig. 22A, 22B, and 22C depict rotated isometric transparent views of a second patch-to-slot waveguide transition 6260 in which the E-polarization of patch 6150 is perpendicular to barrier 1040, in various levels of detail. As can be seen in fig. 22A-22C, the signal probes 6160 are positioned at the edges relative to the patch 6150 (i.e., the signal probes 6160 are disposed near the edges of the patch 6150) and laterally offset from the spacer 1040 (i.e., the signal probes 6160 are not in line with the spacer 1040 as they were in fig. 21A-21C) to produce the desired E-polarization perpendicular to the spacer 1040.

It is contemplated that the geometries of fig. 21A-21C and 22A-22C are castable or moldable, including suitable draft angles that would normally be included by one of ordinary skill in the casting or molding arts suitable for the purposes disclosed herein.

Fig. 23 depicts S (1, 1) and S (1, 2) analytical performance characteristics of the patch-to-slot waveguide transition 6255 depicted in fig. 21A.

Reference is now made to fig. 24-29, which generally relate to an example feed arrangement for an example waveguide antenna system.

Fig. 24 depicts an example waveguide antenna system 7000, for example, similar to TWGA system 6000 of fig. 11 in which like elements are similarly numbered, the example waveguide antenna system 7000 having open waveguides 1000, 1500 and leaky waveguide antennas 2800, 2850 and being configured for on-package antenna 6100 applications, wherein the desired electromagnetic structure for such system 7000 is a structure that can be fed by a low loss waveguide or transmission line and implemented in a serial fashion. As depicted, the open waveguide may be an open TWG 1000 without any bends, or an open TWG 1500 with one or more bends 1520. Such a configuration may be advantageous for use in automotive radar antennas, which is desirably disposed relatively far from the radar MMIC, where manufacturing and implementation costs and complexities need to be considered. The general form of such a desired electromagnetic structure is: the open waveguides 1000, 1500 (generally referred to by reference numeral 2000) feed leaky waveguide antennas 2000, 2800, 2850 (generally referred to by reference numeral 1000). These two elements are distinct from each other in that the open waveguide is intended to have all EM energy confined within its vicinity, while the leaky waveguide antenna is intended to rapidly convert EM energy at its feed point into radiation, which is depicted in fig. 25A and 25B, where fig. 25A and 25B depict a block diagram representation of the basic differences between the open waveguide 1000 (see fig. 25A) and leaky waveguide antenna 2000 (see fig. 25B) that can be implemented in the system 7000 of fig. 24. The fundamental difference between these two elements (i.e., the open waveguide and leaky waveguide antenna) is the type of electromagnetic wave that each structure can support, that is, guided wave (power input equal to P1, power output equal to (substantially equal to) P1) for waveguide 1000 and leaky wave (power input equal to P1, power radiation equal to (substantially equal to) P1, power output equal to (substantially equal to) zero) for antenna 2000. As depicted in fig. 24 and similar to other embodiments disclosed herein, the EM transition portion 100 includes a waveguide transition region 6200 and a TWG 1000, and is configured to: EM energy from the signal feed interface 6205 is coupled to a guided waveguide mode of EM energy, reaches the TWG 1000 via path 6150, and then directs electromagnetic energy to TWGA 2000.

Reference is now made to fig. 26, which depicts an example guided wave. Guided waves are those having a given propagation constantOf (1), wherein/>And/>Is a conventional rectangular unit vector, and wherein each wave number kx, ky and kz is a complex number according to the following equation: k= -iγ = β -iα, where β represents the phase response of the waveguide/antenna, α represents the amount of leakage across the waveguide/antenna, and γ is referred to as the propagation constant. Kz is purely imaginary (except for material loss) in the propagation direction along the z-axis, and the propagation constant (ky) is purely real (evaporation) in the lateral direction along the waveguide interface. On the other hand, leaky waveguide antennas have a propagation constant kz as complex number, where the real part accounts for the radiation loss. Propagation in the transverse direction is also indicative of the complex number of these wave radiations.

By definition, guided waves do not radiate and can be obtained in a myriad of ways. For example, a rectangular dielectric waveguide that confines energy within its dielectric, or a rectangular metal waveguide that confines energy within its metal wall. The open waveguide is simply a metallic structure that guides the wave and is open at one or more of its ends or sides. The only requirement for the open waveguide 1000 is that it supports guided waveguide modes. As depicted in fig. 27, a trench waveguide 1015 having dimensions a1, a2, and b is an example of an open-type waveguide. The main advantages of this type of waveguide are its low loss nature and potentially cost effective fabrication. The E-field guided mode of the trench waveguide 1015 is represented by arrow d in FIG. 27.

The open waveguide 1000 is a natural guiding structure electromagnetically coupled to the leaky waveguide antenna 2000 and feeding the leaky waveguide antenna 2000. Leaky waveguide antennas operate by properly designing the amount of leakage (α) and the phase response (β) across the antenna (see, e.g., α and β in fig. 26). Both the leakage and the phase response may be designed such that the beam of radiation has certain characteristics, namely direction, beam width, side lobe level and pattern shape. Fig. 28A, 28B, and 28C depict examples of this type of antenna structure having an open waveguide 1000 electromagnetically coupled to a leaky waveguide antenna 2000 and feeding the leaky waveguide antenna 2000, respectively, the fig. 28A depicts a top view of the open trench waveguide 1000 electromagnetically coupled to the leaky waveguide antenna 2000 and feeding the leaky waveguide antenna 2000, the fig. 28B depicts a front transparent view of the open trench waveguide 1000, and the fig. 28C depicts a side transparent view of the open trench waveguide 1000; and fig. 29 depicts its radiation performance characteristics. As can be seen in at least fig. 28A, the sidewalls 1020, 1030 of the waveguide 1000 are devoid of electromagnetic interference features, while the sidewalls 2020, 2030 of the leaky waveguide antenna 2000 include: electromagnetic radiation enhancement features 2004 configured to provide desired radiation losses via leaky waveguide antenna 2000 (e.g., as opposed to undulations 2052, 2062).

Reference is now made to fig. 30-31 and 33-50, which generally relate to example waveguide launch structures and associated transition regions and example waveguide radiation correction features for example waveguide antenna systems as disclosed herein.

Fig. 30 depicts a block diagram top plan view of an example transition region 6200 between a signal feed 4000 in the form of an electromagnetic transmission line 4010 and an open waveguide 1000 on a bottom package 6050, such as a Printed Circuit Board (PCB). In an embodiment, the PCB transmission line may be a coplanar waveguide (CPW), microstrip, or stripline. Here, the transition region 6200 is in the form of an edge feed to the open waveguide 1000.

Fig. 31 depicts a block side view of another example transition region 6200 between a signal feed 4000 in the form of an electromagnetic transmission line 4020 and an open waveguide 1000 on a bottom package 6050 such as a PCB. In an embodiment, the PCB transmission line may be a Substrate Integrated Waveguide (SIW), a strip line, or a CPW. Here, the transition region 6200 is of the form: the capacitance or inductance coupled through the slot/aperture 4030 on the conductive surface 4040 of the PCB transmission line 4020 proximate to the signal input 1080 of the open waveguide 1000. As depicted in fig. 31 and similar to other embodiments disclosed herein, a signal feed interface 6205 is provided between the signal feed 4000 and the transition region 6200 to form a portion of the electromagnetic EM transition 100, the EM transition 100 further comprising an open waveguide 1000. In an embodiment, each EM transition section 100 is configured to couple EM energy from signal feed interface 6205 to a guided waveguide mode of EM energy via transition region 6200 to open waveguide section 1000 and then to guide electromagnetic energy to TWGA 2000 (not specifically shown in fig. 31).

Fig. 32A depicts a rotating isometric transparent view of an open waveguide bend 1500, and fig. 32B depicts a top plan view of the open waveguide bend 1500, and fig. 32C and 32D depict the relevant electromagnetic performance characteristics of the embodiment of fig. 32A and 33B for illustrating: bends 1520 in the open waveguide may produce undesirable electromagnetic radiation if not corrected. The open waveguide will ideally guide electromagnetic waves as long as symmetry within the waveguide is maintained. Thus, bending the waveguide in principle produces a myriad of modes of different intensities, some of which are undesirable radiation modes. To compensate for this, the stronger undesirable radiation pattern generated by the bend may be minimized by using one or more of the following: an electromagnetic radiation absorber strategically placed; an electromagnetic radiation choke disposed within the waveguide; structural modification of the height of the spacer within the waveguide, for example by gradually decreasing the height of the spacer from its original height to a smaller height within the bend, such that electromagnetic waves are guided by the spacer-to-wall distance; a structural modification to the inner surface of the open waveguide, the structural modification affecting the phase velocity and/or the waveguide impedance such that the phase velocity and/or the waveguide impedance is constant or substantially constant along the path of the bend; and other structural modifications to the internal features of the slot waveguide within the bend to maintain the phase velocity and/or waveguide impedance constant along the bend.

Referring to fig. 33 in conjunction with fig. 32A, fig. 33 depicts a block-sectional longitudinal view through a bend in a dual-channel open waveguide 1600 having an electromagnetic radiation absorber 1610 disposed above a corresponding dielectric cover 3000 having a dielectric constant Dk value greater than 1, which serves to eliminate or substantially eliminate unwanted electromagnetic radiation from the bend 1520 and improve channel-to-channel isolation. Although the example embodiments disclosed herein depict electromagnetic radiation absorbers 1610 disposed along the bends 1520 of the open waveguide 1500, it should be understood that electromagnetic radiation absorbers may be strategically placed at other locations in the antenna systems disclosed herein for suppressing unwanted radiation. The radar-absorbing material that can be used is not limited and may be in the form of a composite material, i.e., a radar-absorbing material in combination with a polymeric binder. Exemplary radar absorbing materials may be fibrous or particulate, or other forms. For example, the radar absorbing material may be carbon fiber, carbon nanotubes, carbon black, polyaniline, ferrite, or the like. Exemplary polymers for use as the binder may include epoxy, neoprene, polyesters such as polybutylene terephthalate, and the like. The amount of radar-absorbing material is selected to provide the desired radar absorption without significantly adversely affecting the desired properties of the composite, such as processability, etc., and may be, for example, from 1 to 40 volume percent, or from 5 to 30 volume percent, or from 10 to 20 volume percent, each based on the total volume of the composite. Other additives known in the art may be present. An example material suitable as an electromagnetic radiation absorber for the purposes disclosed herein is poly (butylene terephthalate) (PBT) containing 15% by volume carbon fibers.

Referring to fig. 34A and 34B in conjunction with fig. 32A, fig. 34A and 34B depict block-sectional longitudinal views through two versions of a bend 1520 in a dual channel open waveguide 1600 having an electromagnetic radiation choke (quarter wave channel) 1620, which electromagnetic radiation choke 1620 is used to eliminate or substantially eliminate unwanted electromagnetic radiation from the bend and improve channel-to-channel isolation. As depicted, an example choke may be formed within the bend of the open waveguide by creating a quarter wave channel cut into the sidewalls 1020, 1030 of the waveguide. Since electromagnetic radiation exits the waveguide primarily through parallel plate modes, the modes are suppressed by using a quarter wave choke channel to suppress unwanted radiation. As depicted, a quarter wave choke 1620 may be cut horizontally (fig. 34A), vertically (fig. 34A and 34B), or both horizontally and vertically (fig. 34A) in one or both of the sidewalls 1020, 1030 of the open waveguide 1600, which quarter wave choke 1620 may be located in the bend 1520 as depicted, or strategically located elsewhere in the antenna system as disclosed herein to suppress unwanted radiation.

Referring to fig. 35A, 35B and 35C in conjunction with fig. 32A, fig. 35A, 35B and 35C depict block-diagram cross-sectional longitudinal views through three versions of the bend 1520 in the single channel open waveguide 1500 with electromagnetic radiation chokes 1621, 1622, 1623 as alternatives to the electromagnetic radiation chokes depicted in fig. 34A and 34B. Here, the alternative choke includes: a quarter wave channel 1621 (fig. 35A) formed in the draft sidewalls 1020, 1030 of the trough 1010, optionally in combination with the cover 3000; bragg reflector 1622 dielectric or other electromagnetic reflector having total internal reflection characteristics is used in place of dielectric cap 3000; and a dielectric material 1623 having a high dielectric constant (Dk equal to or greater than 6) is used in place of the dielectric cover 3000.

Referring to fig. 36A, 36B, 36C, and 36D in conjunction with fig. 32A, fig. 36A depicts a rotated isometric transparent view of an open waveguide 1500 having one or more bends 1520 of: the one or more bends 1520 have modified baffles 1040 within the bends 1520; and FIG. 36B depicts a transparent side view of the open waveguide 1500; and fig. 36C and 36D depict the relevant electromagnetic performance characteristics of fig. 36A and 36B. Here, the height Hs of the baffle 1040 within the waveguide 1500 is structurally modified, such as by gradually decreasing the height of the baffle from its original height Hs at both ends of the bend 1520 to a smaller height Hsm within the bend 1520, such that electromagnetic waves are guided by the baffle-to-wall distance 1630. An open slot waveguide with a short baffle creates a tight guiding slot mode just above its cut-off frequency. The generated pattern closely guides electromagnetic waves that radiate minimally around the bend as the pattern is closely confined to the baffle and walls.

Referring to fig. 37A, 37B, 37C and 37D in conjunction with fig. 32A, fig. 37A depicts a rotated isometric transparent view of an open waveguide 1500 having the following bends 1520: the bend 1520 has modified floor (base) structures 1050, 1060 within the bend 1520; and fig. 37B depicts a top plan view of the open waveguide 1500; and fig. 37C and 37D depict the relevant electromagnetic performance characteristics of fig. 37A and 37B. Here, the inner surface of the open waveguide is structurally modified, which affects the phase velocity and/or the waveguide impedance such that the phase velocity and/or the waveguide impedance is constant or substantially constant along the path of the bend. Since a slot waveguide may be thought of as two open rectangular waveguides with a septum 1040 in between (see, e.g., fig. 1), the waveguide on the outside of the bend 1520 (represented by associated base reference 1060 in fig. 37B) will have a longer travel path than the waveguide on the inside of the bend 1520 (represented by associated base reference 1050 in fig. 37B). Thus, the two waveguide modes do not travel in phase along the bend, each producing a small amount of radiation, and arrive out of phase with each other at the bend end. However, if the phase velocity of the outer waveguide increases slowly, or the phase velocity of the inner waveguide decreases slowly, the two guided waves will travel in phase, with their corresponding radiation components canceling each other. In an embodiment, this is achieved by: the bottom surface (base) 1060 of the waveguide slot 1010 between the partition 1040 and the corresponding side wall 1020, 1030 is slowly tapered, wherein the tapered profile will determine the most appropriate impedance and correct compensating phase velocity. In the embodiment depicted in fig. 37A, the bottom surface 1060 of the waveguide slot 1010 on the outside of the bend 1520 tapers upward from the bulkhead 1040 toward the outer wall 1030. However, it is contemplated that other tapered profiles of the bottom surfaces 1050, 1060 of the trough 1010 may be suitably employed consistent with the purposes disclosed herein.

Referring to fig. 38 in conjunction with fig. 32A, fig. 38 depicts a block-sectional longitudinal view through a bend 1520 of an open waveguide 1500 having a modified waveguide structure within the bend 1520. Here, other structural modifications are made to the internal features of the slot 1010 of the open waveguide 1500 within the bend 1520 for maintaining the phase velocity and/or waveguide impedance constant along the bend 1520. Example ones of such structural modifications may include one or more of the following: changing the floor height of one channel (indicated by base reference numeral 1050, see fig. 1A) compared to another channel (indicated by base reference numeral 1060, see fig. 1A); changing the width W5 of one channel 1050 compared to the width W6 of the other channel 1060; altering the lateral positioning of the septum 1040 within the slit 1010 to add asymmetry to the structure of the open waveguide 1500; changing the thickness W4 of the spacer 1040; and the height H4 of the spacer 1040 is changed. Such structural modifications may vary along the length of the bend 1520.

Fig. 39A depicts a rotated isometric transparent view of an open waveguide 1500 with the following bends 1520: the bend 1520 has modified wall structures 1020, 1030 within the bend 1520; and fig. 39B depicts a top plan view of the open waveguide 1500; and fig. 39C and 39D depict the relevant electromagnetic performance characteristics of fig. 39A and 39B. As described above, modifying the slot waveguide 1500 within the bend 1520 may be used to adjust EM waves on the inside and outside of the bend 1520 such that the EM waves travel in phase with each other, thereby canceling out the corresponding radiation patterns from each other within the bend 1520. The modification in the bend 1520 acts as a radiation suppressor and is configured to: the phase velocity and the waveguide impedance are affected such that the phase velocity and the waveguide impedance are constant or substantially constant along the path length of the at least one bend 1520. As described above, the slot waveguide 1500 and in particular the slot waveguide bend 1520 can be considered as two open waveguides: an inner waveguide (indicated by reference numeral 1050) located at the inside of the bend 1520, and an outer waveguide (indicated by reference numeral 1060) located at the outside of the bend 1520, wherein the waveguide on the outside of the bend will have a longer path of travel than the waveguide on the inside of the bend. Thus and without modification as disclosed herein, the two waveguide modes on the inside and outside will not travel in phase along the bend and will produce undesirable radiation along the bend. However, if the phase velocity of the inner waveguide and the phase velocity of the outer waveguide are adjusted such that the two waves travel in phase, their corresponding radiation modes will tend to cancel. Additionally, if the impedance of the individual guides is adjusted, their corresponding radiation patterns will tend to cancel each other out. An alternative is to taper the bottom side of the trough, the location of the baffles within the trough, and the width of the trough, as discussed above in connection with fig. 37A, 37B, and 38, and as discussed further below in connection with fig. 40A-40E. In fig. 39A and 39B, another way to achieve the desired effect on EM phase velocity and impedance within the bend 1520 is to pull in the outer sidewall 1030 to narrow the width of the outer waveguide 1060 within the bend 1520, as best seen with reference to fig. 39B. The first sidewall of the at least one bend 1520 is referred to as an inner sidewall 1020; the second side wall of the at least one bend 1520 is referred to as the outer side wall 1030; the first base 1050 has a first width between the first sidewall 1020 and the partition 1040; the second base 1060 has a second width between the partition 1040 and the second side wall 1030; and the first width is greater than the second width. Adjustment is achieved by creating a width difference between the first width of the first base 1050 on the inside of the bend and the second width of the second base 1060 on the outside of the bend so that the two waves travel in phase with equal wave impedance and their corresponding radiation modes cancel.

Referring now to fig. 40A-40E in conjunction with fig. 32A, wherein fig. 40A depicts a block-sectional longitudinal view of an open waveguide 1500 through the exterior of a bend 1520 of the open waveguide 1500, fig. 40B depicts a modified version of fig. 40A with increased inductance within the bend 1520 of the open waveguide 1500, fig. 40C depicts a modified version of fig. 40A with increased capacitance within the bend 1520 of the open waveguide 1500, and fig. 40D and 40E depict the associated electromagnetic performance characteristics of fig. 40B and 40C, respectively.

In the embodiment depicted by the combination of fig. 40A and 40B, the slot waveguide 1500 has a first depth D1 (depicted in fig. 40A) to the first base 1050 and the second base 1060 outside of the at least one bend, and a second depth D2 (depicted in fig. 40B) to the first base 1050 'and the second base 1060' inside of the at least one bend; and the first depth D1 is greater than the second depth D2. By adjusting the depth of the first and second bases inside the bend relative to the respective depths outside the bend, a change in the inductive impedance of the waveguide can be achieved, and by providing a matching impedance via the inductance inside the bend, both the inner and outer waves inside the bend can be made to travel in phase such that their corresponding radiation modes cancel.

In the embodiment depicted by the combination of fig. 40A and 40C, the barrier 1040 has a first wall thickness T1 outside of the at least one bend 1520 and a second wall thickness T2 inside of the at least one bend 1520; and the first wall thickness T1 is smaller than the second wall thickness T2. By adjusting the wall thickness of the baffle 1040' inside the bend 1520 relative to the wall thickness outside the bend 1520, a change in capacitance of the waveguide 1500 can be achieved, and by providing a matching impedance via the capacitance inside the bend, both the inside and outside waves inside the bend can be made to travel in phase such that their corresponding radiation modes cancel.

1A-40C, it is to be understood that aspects of the embodiments disclosed herein conform to, but are not limited to, at least the following aspects and/or combinations of aspects.

Aspect 1. A waveguide antenna system comprising: an electromagnetic EM transition section comprising a transition region having a signal feed interface and an open waveguide section, the EM transition section configured to couple EM energy from the signal feed interface to a guided waveguide mode of EM energy to the open waveguide section via the transition region; and a leaky waveguide antenna portion configured and arranged to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support electromagnetic energy transfer from a signal feed structure to the leaky waveguide antenna portion.

Aspect 2. The waveguide antenna system according to aspect 1, wherein: the EM transition portion is configured to support EM energy transfer from a planar signal feed structure to the leaky waveguide antenna portion.

Aspect 3 the waveguide antenna system according to any one of aspects 1 to 2, wherein: the open waveguide section includes an open slot waveguide.

Aspect 4 the waveguide antenna system according to any one of aspects 1 to 2, wherein: the open waveguide section includes an open trench waveguide.

Aspect 5 the waveguide antenna system according to any one of aspects 1 to 4, wherein: the open waveguide section is free of discontinuities along its respective length; the leaky waveguide antenna portion including a plurality of discontinuities along respective lengths thereof; and the open waveguide section is electromagnetically coupled to the leaky waveguide antenna portion using an electromagnetic coupling with the leaky waveguide antenna portion, wherein a change in discontinuity transitions from an absence of discontinuity of the open waveguide section to a substantial discontinuity of the leaky waveguide antenna portion.

Aspect 6. A waveguide antenna system comprising: a plurality of waveguide antenna systems according to any of aspects 1-5 configured for on-package antenna applications.

Aspect 7. A waveguide antenna system, comprising: a plurality of waveguide antenna systems according to any of aspects 1 to 5 configured for use in a patch application on a printed circuit board.

Aspect 8 the waveguide antenna system according to any one of aspects 6 to 7, wherein: in the transmit mode and configuration, each open waveguide section is arranged and configured to: receiving electromagnetic energy from an antenna component on a package or a patch component on a printed circuit board and delivering the electromagnetic energy to a corresponding leaky waveguide antenna portion; and in a receive mode and configuration, each open waveguide section is arranged and configured to: electromagnetic energy from a corresponding leaky waveguide antenna portion is received and delivered to an on-package antenna component or an on-printed circuit board patch component.

Aspect 9. An open waveguide signal feed system, comprising: a printed circuit board having a signal feed and a signal feed output; an open waveguide having a signal feed input port; a transition region disposed between and in signal communication with the signal feed output and the signal feed input port; wherein the signal feed comprises a microstrip, coplanar waveguide or stripline; wherein the signal feed output comprises a patch or probe.

Aspect 10 the open waveguide signal feed system of aspect 9, wherein: the transition region includes a closed waveguide.

Aspect 11 the open waveguide signal feed system of aspect 9, wherein: the transition region includes an edge feed between the signal feed output and the signal feed input port.

Aspect 12 the open waveguide signal feed system of aspect 9, wherein: the transition region includes an aperture at the signal feed output that is directly electromagnetically coupled to the signal feed input port.

Aspect 13 an open waveguide section comprising: at least one bend in a slot waveguide, the at least one bend in a propagation direction of an electromagnetic wave in the slot waveguide, the slot waveguide comprising: the trough having opposed first and second side walls, a baffle disposed between the first and second side walls, a first base disposed between the first and second side walls, and a second base disposed between the baffle and the second side wall, wherein at least all surfaces of the first, second, baffle, first base, and second base within the trough are electrically conductive; and an electromagnetic radiation suppressor, the electromagnetic radiation suppressor being strategically configured and disposed to: suppressing unwanted electromagnetic radiation that can be emitted from the at least one bend in the absence of the electromagnetic radiation suppressor.

Aspect 14 the open waveguide section according to aspect 13, wherein: the electromagnetic radiation inhibitor includes an electromagnetic radiation absorbing material disposed over an upper open end of the at least one bend of the slot waveguide.

Aspect 15 the open waveguide section of aspect 13, wherein: the electromagnetic radiation inhibitor includes an electromagnetic choke mechanism disposed within the at least one bend of the slot waveguide.

Aspect 16 the open waveguide section according to aspect 15, wherein: the electromagnetic choke mechanism includes at least one quarter-wavelength channel cut into each of the first and second sidewalls of the slot.

Aspect 17 the open waveguide section of aspect 16, wherein: the at least one quarter wave channel comprises at least one symmetrically arranged channel disposed in the first and second sidewalls of the trough.

Aspect 18 the open waveguide section according to any one of aspects 16 to 17, wherein: the at least one quarter wave channel includes a horizontal portion and a continuous vertical portion.

Aspect 19 the open waveguide section according to any one of aspects 16 to 17, wherein: the first and second sidewalls of the groove have angled sidewalls, and the at least one quarter wave channel is formed in each corresponding angled sidewall.

Aspect 20 the open waveguide section according to aspect 15, wherein: the electromagnetic choke mechanism includes an electromagnetic reflector in the form of a cap having TIR characteristics, the electromagnetic reflector disposed over the upper open end of the at least one bend of the slot waveguide and extending from the first sidewall to the second sidewall across the at least one bend of the slot, the TIR reflector including a dielectric material having a dielectric constant that varies in a direction orthogonal to the cap, the varying dielectric constant producing total internal reflection.

Aspect 21 the open waveguide section according to aspect 15, wherein: the electromagnetic choke mechanism includes a dielectric medium disposed over the upper open end of the at least one bend of the slot waveguide and extending from the first sidewall to the second sidewall across the at least one bend of the slot, the dielectric medium including a dielectric material having a dielectric constant greater than 6.

Aspect 22. The open waveguide section of aspect 13, wherein: the electromagnetic radiation suppressor includes a modified baffle having a reduced height within the at least one bend that is less than an original height of the baffle outside the at least one bend.

Aspect 23 the open waveguide section of aspect 22, wherein: the modified baffle tapers downwardly from the original height to the reduced height.

Aspect 24 the open waveguide section of aspect 13, wherein: the electromagnetic radiation inhibitor includes a modified inner surface of the slot within the at least one bend, the modified inner surface of the slot configured to: the phase velocity and/or the waveguide impedance are influenced such that the phase velocity and/or the waveguide impedance is constant or substantially constant along the path length of the at least one bend.

Aspect 25 the open waveguide section of aspect 24, wherein: the modified inner surface of the slot includes a tapered bottom surface of the waveguide slot between the baffle and at least one of the first and second sidewalls.

Aspect 26 the open waveguide section of aspect 25, wherein: the tapered bottom surface tapers upwardly from the baffle toward an outer wall of the exterior of the at least one bend.

Aspect 27 the open waveguide section of aspect 24, wherein: the modified inner surface of the groove includes a difference in height between the first base of the groove and the second base of the groove.

Aspect 28 the open waveguide section of aspect 24, wherein the slot comprises a first slot portion between the first sidewall and the bulkhead and a second slot portion between the second sidewall and the bulkhead, wherein the first slot portion is disposed on an inside bend of the at least one bend and the second slot portion is disposed on an outside bend of the at least one bend, and further wherein: the modified inner surface of the groove includes a width difference between the first groove portion and the second groove portion.

Aspect 29 the open waveguide section of aspect 24, wherein: the modified inner surface of the groove includes an asymmetric lateral positioning of the baffle within the at least one bend relative to the first and second sidewalls.

Aspect 30 the open waveguide section of aspect 24, wherein: the modified inner surface of the groove includes a thickness of the baffle within the at least one bend that is different than a thickness of the baffle outside the at least one bend.

Aspect 31 the open waveguide section of aspect 24, wherein: the first sidewall is an inner sidewall of the at least one bend; the second side wall is an outer side wall of the at least one bend; the first base has a first width between the first sidewall and the partition defining a first slot portion disposed on an inner side bend of the at least one bend; the second base has a second width between the partition and the second sidewall, the second width defining a second slot portion disposed on an outer bend of the at least one bend; and the first width is greater than the second width.

Aspect 32 the open waveguide section of aspect 31, wherein: the cross section of the second slot portion inside the at least one bend has a smaller width than a corresponding cross-sectional width outside the at least one bend for increasing the capacitance of the second slot portion inside the at least one bend.

Aspect 33 the open waveguide section according to any one of aspects 31 to 32, wherein: the cross section of the first slot portion inside the at least one bend has a width that is larger than a corresponding cross-sectional width of the at least one bend outside for reducing the capacitance of the first slot portion inside the at least one bend.

Aspect 34. The open waveguide section of aspect 32, wherein: the second slot portion has a cross-sectional width inside the at least one bend having a width dimension as low as 200 microns or less.

Aspect 35 the open waveguide section of aspect 33, wherein: the first slot portion has a cross-sectional width inside the at least one bend having the following width dimensions: the width dimension is no greater than one half a wavelength of an operating frequency of the open waveguide section inside the at least one bend.

Aspect 36 the open waveguide section of aspect 24, wherein: the slot waveguide has a first depth to the first base and the second base of a curved outer portion of the at least one curved portion and a second depth to the first base and the second base of a curved inner portion of the at least one curved portion; and the first depth of the curved outer portion of the curved portion is greater than the second depth of the curved inner portion of the curved portion.

The open waveguide section according to any one of aspects 24 and 36, wherein the slot comprises a first slot portion between the first sidewall and the bulkhead and a second slot portion between the second sidewall and the bulkhead, and further wherein: the cross section of the second slot portion inside the at least one bend has a depth smaller than a corresponding cross-sectional depth outside the at least one bend for increasing the impedance of the second slot portion inside the at least one bend and for increasing the phase velocity of an electromagnetic wave propagating through the second slot portion when the electromagnetic wave is present.

Aspect 38 the open waveguide section of aspect 37, wherein: the cross section of the first slot portion inside the at least one bend has a depth greater than a corresponding cross-sectional depth outside the at least one bend for reducing the impedance of the first slot portion inside the at least one bend and for reducing the phase velocity of an electromagnetic wave propagating through the first slot portion when the electromagnetic wave is present.

Aspect 39 the open waveguide section of aspect 37, wherein: the second groove portion has a cross-sectional depth at least as deep as the height of the baffle.

Aspect 40 the open waveguide section of aspect 38, wherein: the cross-sectional depth of the first slot portion inside the at least one bend increases by at most a quarter of a wavelength of an operating frequency of the open waveguide section inside the at least one bend relative to the cross-sectional depth of the first slot portion outside the at least one bend.

Aspect 41 the open waveguide section of aspect 24, wherein: the separator has a first wall thickness outside the at least one bend and a second wall thickness inside the at least one bend; and the first wall thickness is less than the second wall thickness.

Aspect 42, an open waveguide antenna comprising: a trough having opposed first and second side walls, a partition disposed between the first and second side walls, a first base disposed between the first and second side walls, and a second base disposed between the partition and the second side wall; wherein at least one or more of the surfaces of the first side wall, the second side wall, the partition, the first base, and the second base inside the groove are electrically conductive; wherein the first base has a first sequence of undulations longitudinally disposed along the length of the trough; wherein the first sequence of undulations alternately and sequentially follows a first curved path and a second curved path, the second curved path being asymmetric with the first curved path; wherein the second base has a second sequence of undulations disposed longitudinally along the length of the trough; wherein the undulations of the second sequence alternately and sequentially follow the second curved path and the first curved path; wherein the first and second curved paths alternate along the length of the slot from one side of the separator to the other side of the separator.

Aspect 43 the open waveguide antenna of aspect 42, wherein: the first base and the second base are electrically conductive at all surfaces inside the slot.

Aspect 44 the open waveguide antenna of aspect 42, wherein: at least a portion of the undulations of the first sequence comprise a dielectric material.

Aspect 45 the open waveguide antenna of aspect 42, wherein: at least a portion of the undulations of the second sequence comprise a dielectric material.

Aspect 46 the open waveguide antenna of any one of aspects 42 to 45, wherein: the slot is a unitary non-conductive structure having a conductive surface formed thereon.

Aspect 47 the open waveguide antenna of any one of aspects 42-46, wherein: the partition extends upwardly from the first base and the second base.

Aspect 48 the open waveguide antenna according to any one of aspects 42 to 47, wherein: the exposed surfaces of the first sidewall, the second sidewall, and the baffle are non-parallel to one another along the length of the slot.

Aspect 49 the open waveguide antenna according to any one of aspects 42 to 48, wherein: the height of the partition plate is smaller than that of the first side wall or the second side wall.

Aspect 50 the open waveguide antenna of any one of aspects 42 to 49, wherein: the baffle is centrally disposed between the first sidewall and the second sidewall.

Aspect 51 the open waveguide antenna according to any one of aspects 42 to 50, wherein: the undulations of the first sequence and the undulations of the second sequence are asymmetric with respect to the separator.

Aspect 52 the open waveguide antenna according to any one of aspects 42 to 51, wherein: the undulations of the first sequence alternate in elevation along the length of the slot between the first curved path and the second curved path.

Aspect 53 the open waveguide antenna according to any one of aspects 42 to 52, wherein: the undulations of the second sequence alternate in elevation along the length of the slot between the second curved path and the first curved path.

Aspect 54 the open waveguide antenna of any one of aspects 42-53, wherein: the first curved path is a first waveform having alternating peaks and valleys, the first waveform being a composite of a smooth waveform multiplied by a square wave, when viewed in side elevation of the trough.

Aspect 55 the open waveguide antenna of aspect 54, wherein: the second curved path is a second waveform having alternating peaks and valleys, the second waveform being a composite of a smooth waveform multiplied by a square wave, when viewed in side elevation of the channel.

Aspect 56 the open waveguide antenna of aspect 55, wherein: the second smooth waveform and the first smooth waveform have different elevations in both peaks and valleys between the ends of the trough and at all points inboard of the ends.

Aspect 57 the open waveguide antenna according to any one of aspects 42 to 56, further comprising: a dielectric cover disposed over, covering and extending at least a portion of the length of the slot, and extending from the first sidewall across the slot to the second sidewall, the dielectric cover comprising a dielectric material having a dielectric constant greater than one.

Aspect 58 the open waveguide antenna of aspect 57, wherein: the upper outer surface of the dielectric cap has a longitudinal indent extending along the length of the slot.

Aspect 59 the open waveguide antenna of aspect 58, wherein: the longitudinal indentation is centrally located along the length of the slot.

Aspect 60 the open waveguide antenna of any one of aspects 58-59, wherein: the longitudinal dimples have a concave cross-sectional profile.

Aspect 61 the open waveguide antenna of aspect 60, wherein: the concave cross-sectional profile can be represented by a polynomial curve.

Aspect 62 the open waveguide antenna of aspect 57, wherein: the upper outer surface of the dielectric cover has a longitudinal protrusion extending along the length of the slot.

Aspect 63 the open waveguide antenna of aspect 62, wherein: the longitudinal projection is centrally disposed along the length of the slot.

Aspect 64 the open waveguide antenna of any one of aspects 62 to 63, wherein: the longitudinal projection has a convex cross-sectional profile.

Aspect 65 the open waveguide antenna of aspect 64, wherein: the convex cross-sectional profile can be represented by a polynomial curve.

Aspect 66. The open waveguide antenna of aspect 57, wherein: the lower inner surface of the dielectric cover has a longitudinal indent extending along the length of the slot.

Aspect 67. The open waveguide antenna of aspect 66, wherein: the longitudinal indentation is centrally located along the length of the slot.

Aspect 68 the open waveguide antenna of any one of aspects 66-67, wherein: the longitudinal dimples have a concave cross-sectional profile.

Aspect 69 the open waveguide antenna of aspect 68, wherein: the concave cross-sectional profile can be represented by a polynomial curve.

Aspect 70 the open waveguide antenna of aspect 57, wherein: the lower inner surface of the dielectric cover has a longitudinal protrusion extending along the length of the slot.

Aspect 71 the open waveguide antenna of aspect 70, wherein: the longitudinal projection is centrally disposed along the length of the slot.

Aspect 72 the open waveguide antenna according to any one of aspects 70 to 71, wherein: the longitudinal projection has a convex cross-sectional profile.

Aspect 73 the open waveguide antenna of aspect 72, wherein: the convex cross-sectional profile can be represented by a polynomial curve.

Aspect 74 the open waveguide antenna of any one of aspects 42-73, having a moldable configuration, wherein: the moldable configuration comprises one or more of the following: (i) Positive fabrication features that do not allow the planar surface features to stick during the barrel plating process; (ii) One or more screw locations incorporated into the construct; (iii) A drawn shell construction for reducing material consumption and warpage; (iv) An integrally formed recess for reducing sticking tendency during electroplating; (v) A mold draft angle of 2 degrees or more provided on the top side; (vi) A molding draft angle of 4 degrees or more provided on the bottom side; and (vii) a molded parting line located adjacent the bottom surface.

Aspect 75 the open waveguide antenna according to any one of aspects 42 to 73, wherein: the slot is of die-cast construction.

Aspect 76 the open waveguide antenna of any one of aspects 42-73, wherein: the slot is of injection molded plastic construction.

Aspect 77 the open waveguide antenna of aspect 76, wherein: the injection molded plastic construction is metallized to provide a conductive surface thereon.

Aspect 78 an open waveguide antenna system comprising an open waveguide antenna according to any one of aspects 42 to 77, the open waveguide antenna system further comprising: a signal feed port provided at one end of the slot; and an electrical shorting circuit disposed at a second opposite end of the slot.

Aspect 79 the open waveguide antenna system of aspect 78, further comprising: a conductive surface disposed near an upper end of the slot; wherein the electrical shorting circuit is electrically connected to the conductive surface; and wherein the conductive surface has an aperture configured and arranged to expose an upper end of the slot for electromagnetic coupling with the conductive surface.

Aspect 80 the open waveguide antenna system of any one of aspects 78-79, wherein: the patch-to-slot guiding transition is configured such that the patch E polarization is parallel to the baffle.

Aspect 81 the open waveguide antenna system of any one of aspects 78 to 79, wherein: the patch-to-slot guiding transition is configured such that the patch E polarization is perpendicular to the baffle.

Aspect 82. A multi-channel open waveguide antenna comprising: a plurality of open waveguide antennas according to any one of aspects 42 to 63 arranged in a side-by-side configuration with a center-to-center spacing of adjacent slots equal to or greater than λ/2 and equal to or less than 10 times λ, where λ is a wavelength at an operating frequency of the multi-channel open waveguide antenna.

Aspect 83 the multi-channel open waveguide antenna according to aspect 82, wherein: the side-by-side configuration is a multi-monomer construction.

Aspect 84 the multi-channel open waveguide antenna according to any one of aspects 82 to 83, wherein: the side-by-side configuration includes a plurality of receiver channels and a plurality of transmitter channels.

Aspect 85 the multi-channel open waveguide antenna of aspect 84, wherein: the plurality of receiver channels includes at least 4 receiver channels.

Aspect 86 the multi-channel open waveguide antenna of aspect 84, wherein: the plurality of transmitter channels includes at least 3 transmitter channels.

Aspect 87 an open waveguide antenna system comprising: a signal feed; an EM transition portion, the EM transition portion comprising: a signal feed interface disposed at a first end of the EM transition portion and in EM communication with the signal feed, and an open waveguide section having a second end opposite the first end; and an open waveguide antenna according to any one of aspects 42 to 61, the open waveguide antenna being arranged for EM communication with the second end of the EM transition portion; wherein the EM transition portion is configured to: coupling EM energy from the signal feed to the signal feed interface to a guided waveguide mode of EM energy, to the open waveguide section, and to the open waveguide antenna.

Aspect 88 the open waveguide antenna system of aspect 87, wherein: the signal feed includes any one of the following: an in-package antenna; a circuit board structure; a patch; a signal probe; a signal loop; a signal aperture.

Aspect 89 an open waveguide antenna system comprising: packaging an antenna; the open waveguide antenna of any one of aspects 42-61; and an EM transition disposed between and in EM signal communication with the on-package antenna and the open waveguide antenna.

Aspect 90 the open waveguide antenna system of aspect 89, wherein: the EM transition includes a ridge waveguide.

Aspect 91 the open waveguide antenna system of aspect 89, wherein: the EM transition includes a rectangular waveguide.

Aspect 92 the open waveguide antenna system of aspect 89, wherein: the EM transition includes a waveguide bend.

Some embodiments disclosed herein may have one or more of the following advantages: high gain is achieved simultaneously with minimal feed and transition losses; being able to customize a given antenna pattern and high bandwidth; low sensitivity to small manufacturing variations compared to prior art DRA waveguide systems with dielectrics; and a high efficiency antenna system formed by strategically combining open waveguide sections and leaky waveguide antenna sections, which results in an antenna system suitable for modern multiple-input multiple-output (MIMO) automotive radar antennas.

As used herein, the phrase "equal to about" is intended to explain manufacturing tolerances and/or insubstantial deviations from nominal values that do not affect the objects disclosed herein and fall within the scope of the appended claims.

Although certain combinations of individual features have been described and illustrated herein, it is understood that such certain combinations of features are for illustration purposes only and that any combination of any such individual features can be employed depending on the implementation, whether or not such combination is explicitly shown and is consistent with the disclosure herein. Any and all such combinations of features disclosed herein are contemplated herein, are considered to be within the purview of one skilled in the art when considering the application as a whole, and are considered to be within the scope of the application disclosed herein, so long as they fall within the scope of the application as defined by the appended claims in a manner that would be understood by one skilled in the art.

Although the invention has been described herein with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the claims. Many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment or embodiments disclosed as the best or only mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In the drawings and specification, there have been disclosed example embodiments and, although specific terms and/or dimensions may be employed, they are unless otherwise stated used in a generic, descriptive and/or descriptive sense only and not for purposes of limitation, the scope of the claims therefore not being so limited. When an element such as a layer, film, region, substrate or other described feature is referred to as being "on" or "engaged with" another element, it can be directly on or engaged with the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly engaged with" another element, there are no intervening elements present. The use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. The use of the terms "a," "an," etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The use of the terms "top," "bottom," "upper," "lower," "left," "right," "front," "rear," etc., or any reference to an orientation, does not denote a limitation of structure, but rather denote a relative structural relationship between one or more of the associated features disclosed herein, since the structure may be viewed from more than one orientation. The term "comprising" as used herein does not exclude the possibility of including one or more additional features. Also, any background information provided herein is provided for the purpose of disclosing information that the applicant believes may be relevant to the invention disclosed herein. It is not necessarily admitted that any such background information constitutes prior art against the embodiments of the invention disclosed herein.

Claims

1. A waveguide antenna system comprising:

An electromagnetic EM transition section comprising a transition region having a signal feed interface and an open waveguide section, the EM transition section configured to couple EM energy from the signal feed interface to a guided waveguide mode of EM energy to the open waveguide section via the transition region; and

A leaky waveguide antenna portion configured and arranged to radiate electromagnetic energy received from the open waveguide section;

Wherein the EM transition portion is electromagnetically coupled to the leaky waveguide antenna portion, the EM transition portion being configured to support electromagnetic energy transfer from a signal feed structure to the leaky waveguide antenna portion.

2. The waveguide antenna system of claim 1, wherein:

the EM transition portion is configured to support EM energy transfer from a planar signal feed structure to the leaky waveguide antenna portion.

3. The waveguide antenna system of any of claims 1-2, wherein:

The open waveguide section includes an open slot waveguide.

4. The waveguide antenna system of any of claims 1-2, wherein:

the open waveguide section includes an open trench waveguide.

5. The waveguide antenna system of any of claims 1-4, wherein:

the open waveguide section is free of discontinuities along its respective length;

The leaky waveguide antenna portion including a plurality of discontinuities along respective lengths thereof; and

The open waveguide section is electromagnetically coupled to the leaky waveguide antenna portion using an electromagnetic coupling with the leaky waveguide antenna portion, wherein a change in discontinuity transitions from an absence of discontinuity in the open waveguide section to a substantial discontinuity in the leaky waveguide antenna portion.

6. A waveguide antenna system comprising:

a plurality of waveguide antenna systems according to any of claims 1-5 configured for on-package antenna applications.

7. A waveguide antenna system comprising:

A plurality of waveguide antenna systems according to any of claims 1-5 configured for use in printed circuit board patch applications.

8. The waveguide antenna system of any of claims 6-7, wherein:

In the transmit mode and configuration, each open waveguide section is arranged and configured to: receiving electromagnetic energy from an antenna component on a package or a patch component on a printed circuit board and delivering the electromagnetic energy to a corresponding leaky waveguide antenna portion; and

In a receive mode and configuration, each open waveguide section is arranged and configured to: electromagnetic energy from a corresponding leaky waveguide antenna portion is received and delivered to an on-package antenna component or an on-printed circuit board patch component.

9. An open waveguide signal feed system comprising:

a printed circuit board having a signal feed and a signal feed output;

an open waveguide having a signal feed input port;

A transition region disposed between and in signal communication with the signal feed output and the signal feed input port;

Wherein the signal feed comprises a microstrip, coplanar waveguide or stripline;

wherein the signal feed output comprises a patch or probe.

10. The open waveguide signal feed system of claim 9, wherein:

The transition region includes a closed waveguide.

11. The open waveguide signal feed system of claim 9, wherein:

The transition region includes an edge feed between the signal feed output and the signal feed input port.

12. The open waveguide signal feed system of claim 9, wherein:

the transition region includes an aperture at the signal feed output that is directly electromagnetically coupled to the signal feed input port.

13. An open waveguide section comprising:

At least one bend in a slot waveguide, the at least one bend in a propagation direction of an electromagnetic wave in the slot waveguide, the slot waveguide comprising: the trough having opposed first and second side walls, a baffle disposed between the first and second side walls, a first base disposed between the first and second side walls, and a second base disposed between the baffle and the second side wall, wherein at least all surfaces of the first, second, baffle, first base, and second base within the trough are electrically conductive; and

An electromagnetic radiation suppressor, said electromagnetic radiation suppressor being strategically configured and arranged to: suppressing unwanted electromagnetic radiation that can be emitted from the at least one bend in the absence of the electromagnetic radiation suppressor.

14. The open waveguide section of claim 13, wherein:

The electromagnetic radiation inhibitor includes an electromagnetic radiation absorbing material disposed over an upper open end of the at least one bend of the slot waveguide.

15. The open waveguide section of claim 13, wherein:

The electromagnetic radiation inhibitor includes an electromagnetic choke mechanism disposed within the at least one bend of the slot waveguide.

16. The open waveguide section of claim 15, wherein:

The electromagnetic choke mechanism includes at least one quarter-wavelength channel cut into each of the first and second sidewalls of the slot.

17. The open waveguide section of claim 16, wherein:

The at least one quarter wave channel comprises at least one symmetrically arranged channel disposed in the first and second sidewalls of the trough.

18. The open waveguide section of any one of claims 16 to 17, wherein:

the at least one quarter wave channel includes a horizontal portion and a continuous vertical portion.

19. The open waveguide section of any one of claims 16 to 17, wherein:

The first and second sidewalls of the groove have angled sidewalls, and the at least one quarter wave channel is formed in each corresponding angled sidewall.

20. The open waveguide section of claim 15, wherein:

The electromagnetic choke mechanism includes an electromagnetic reflector in the form of a cap having TIR characteristics, the electromagnetic reflector disposed over the upper open end of the at least one bend of the slot waveguide and extending from the first sidewall to the second sidewall across the at least one bend of the slot, the TIR reflector including a dielectric material having a dielectric constant that varies in a direction orthogonal to the cap, the varying dielectric constant producing total internal reflection.

21. The open waveguide section of claim 15, wherein:

The electromagnetic choke mechanism includes a dielectric medium disposed over the upper open end of the at least one bend of the slot waveguide and extending from the first sidewall to the second sidewall across the at least one bend of the slot, the dielectric medium including a dielectric material having a dielectric constant greater than 6.

22. The open waveguide section of claim 13, wherein:

The electromagnetic radiation suppressor includes a modified baffle having a reduced height within the at least one bend that is less than an original height of the baffle outside the at least one bend.

23. The open waveguide section of claim 22, wherein:

the modified baffle tapers downwardly from the original height to the reduced height.

24. The open waveguide section of claim 13, wherein:

The electromagnetic radiation inhibitor includes a modified inner surface of the slot within the at least one bend, the modified inner surface of the slot configured to: the phase velocity and/or the waveguide impedance are influenced such that the phase velocity and/or the waveguide impedance is constant or substantially constant along the path length of the at least one bend.

25. The open waveguide section of claim 24, wherein:

The modified inner surface of the slot includes a tapered bottom surface of the waveguide slot between the baffle and at least one of the first and second sidewalls.

26. The open waveguide section of claim 25, wherein:

The tapered bottom surface tapers upwardly from the baffle toward an outer wall of the exterior of the at least one bend.

27. The open waveguide section of claim 24, wherein:

the modified inner surface of the groove includes a difference in height between the first base of the groove and the second base of the groove.

28. The open waveguide section of claim 24, wherein the slot comprises a first slot portion between the first sidewall and the bulkhead and a second slot portion between the second sidewall and the bulkhead, wherein the first slot portion is disposed on an inside bend of the at least one bend and the second slot portion is disposed on an outside bend of the at least one bend, and further wherein:

the modified inner surface of the groove includes a width difference between the first groove portion and the second groove portion.

29. The open waveguide section of claim 24, wherein:

The modified inner surface of the groove includes an asymmetric lateral positioning of the baffle within the at least one bend relative to the first and second sidewalls.

30. The open waveguide section of claim 24, wherein:

The modified inner surface of the groove includes a thickness of the baffle within the at least one bend that is different than a thickness of the baffle outside the at least one bend.

31. The open waveguide section of claim 24, wherein:

the first sidewall is an inner sidewall of the at least one bend;

the second side wall is an outer side wall of the at least one bend;

The first base has a first width between the first sidewall and the partition defining a first slot portion disposed on an inner side bend of the at least one bend;

the second base has a second width between the partition and the second sidewall, the second width defining a second slot portion disposed on an outer bend of the at least one bend; and

The first width is greater than the second width.

32. The open waveguide section of claim 31, wherein:

The cross section of the second slot portion inside the at least one bend has a smaller width than a corresponding cross-sectional width outside the at least one bend for increasing the capacitance of the second slot portion inside the at least one bend.

33. The open waveguide section of any one of claims 31 to 32, wherein:

The cross section of the first slot portion inside the at least one bend has a width that is larger than a corresponding cross-sectional width of the at least one bend outside for reducing the capacitance of the first slot portion inside the at least one bend.

34. The open waveguide section of claim 32, wherein:

The second slot portion has a cross-sectional width inside the at least one bend having a width dimension as low as 200 microns or less.

35. The open waveguide section of claim 33, wherein:

The first slot portion has a cross-sectional width inside the at least one bend having the following width dimensions: the width dimension is no greater than one half a wavelength of an operating frequency of the open waveguide section inside the at least one bend.

36. The open waveguide section of claim 24, wherein:

The slot waveguide has a first depth to the first base and the second base of a curved outer portion of the at least one curved portion and a second depth to the first base and the second base of a curved inner portion of the at least one curved portion; and

The first depth of the curved outer portion of the curved portion is greater than the second depth of the curved inner portion of the curved portion.

37. The open waveguide section of any one of claims 24 and 36, wherein the slot comprises a first slot portion between the first sidewall and the bulkhead and a second slot portion between the second sidewall and the bulkhead, and further wherein:

The cross section of the second slot portion inside the at least one bend has a depth smaller than a corresponding cross-sectional depth outside the at least one bend for increasing the impedance of the second slot portion inside the at least one bend and for increasing the phase velocity of an electromagnetic wave propagating through the second slot portion when the electromagnetic wave is present.

38. The open waveguide section of claim 37, wherein:

The cross section of the first slot portion inside the at least one bend has a depth greater than a corresponding cross-sectional depth outside the at least one bend for reducing the impedance of the first slot portion inside the at least one bend and for reducing the phase velocity of an electromagnetic wave propagating through the first slot portion when the electromagnetic wave is present.

39. The open waveguide section of claim 37, wherein:

The second groove portion has a cross-sectional depth at least as deep as the height of the baffle.

40. The open waveguide section of claim 38, wherein:

The cross-sectional depth of the first slot portion inside the at least one bend increases by at most a quarter of a wavelength of an operating frequency of the open waveguide section inside the at least one bend relative to the cross-sectional depth of the first slot portion outside the at least one bend.

41. The open waveguide section of claim 24, wherein:

The separator has a first wall thickness outside the at least one bend and a second wall thickness inside the at least one bend; and

The first wall thickness is less than the second wall thickness.

42. An open waveguide antenna comprising:

A trough having opposed first and second side walls, a partition disposed between the first and second side walls, a first base disposed between the first and second side walls, and a second base disposed between the partition and the second side wall;

Wherein at least one or more of the surfaces of the first side wall, the second side wall, the partition, the first base, and the second base inside the groove are electrically conductive;

Wherein the first base has a first sequence of undulations longitudinally disposed along the length of the trough;

Wherein the first sequence of undulations alternately and sequentially follows a first curved path and a second curved path, the second curved path being asymmetric with the first curved path;

wherein the second base has a second sequence of undulations disposed longitudinally along the length of the trough;

Wherein the undulations of the second sequence alternately and sequentially follow the second curved path and the first curved path;

Wherein the first and second curved paths alternate along the length of the slot from one side of the separator to the other side of the separator.

43. The open waveguide antenna of claim 42, wherein:

the first base and the second base are electrically conductive at all surfaces inside the slot.

44. The open waveguide antenna of claim 42, wherein:

at least a portion of the undulations of the first sequence comprise a dielectric material.

45. The open waveguide antenna of claim 42, wherein:

At least a portion of the undulations of the second sequence comprise a dielectric material.

46. The open waveguide antenna of any one of claims 42 to 45, wherein:

the slot is a unitary non-conductive structure having a conductive surface formed thereon.

47. The open waveguide antenna of any one of claims 42 to 46, wherein:

the partition extends upwardly from the first base and the second base.

48. The open waveguide antenna of any one of claims 42-47, wherein:

the exposed surfaces of the first sidewall, the second sidewall, and the baffle are non-parallel to one another along the length of the slot.

49. The open waveguide antenna of any one of claims 42 to 48, wherein:

The height of the partition plate is smaller than that of the first side wall or the second side wall.

50. The open waveguide antenna of any one of claims 42 to 49, wherein:

the baffle is centrally disposed between the first sidewall and the second sidewall.

51. The open waveguide antenna of any one of claims 42 to 50, wherein:

the undulations of the first sequence and the undulations of the second sequence are asymmetric with respect to the separator.

52. The open waveguide antenna of any one of claims 42 to 51, wherein:

the undulations of the first sequence alternate in elevation along the length of the slot between the first curved path and the second curved path.

53. The open waveguide antenna of any one of claims 42 to 52, wherein:

The undulations of the second sequence alternate in elevation along the length of the slot between the second curved path and the first curved path.

54. The open waveguide antenna of any one of claims 42 to 53, wherein:

the first curved path is a first waveform having alternating peaks and valleys, the first waveform being a composite of a smooth waveform multiplied by a square wave, when viewed in side elevation of the trough.

55. The open waveguide antenna of claim 54, wherein:

the second curved path is a second waveform having alternating peaks and valleys, the second waveform being a composite of a smooth waveform multiplied by a square wave, when viewed in side elevation of the channel.

56. The open waveguide antenna of claim 55, wherein:

the second smooth waveform and the first smooth waveform have different elevations in both peaks and valleys between the ends of the trough and at all points inboard of the ends.

57. The open waveguide antenna of any one of claims 42 to 56, further comprising:

A dielectric cover disposed over, covering and extending at least a portion of the length of the slot, and extending from the first sidewall across the slot to the second sidewall, the dielectric cover comprising a dielectric material having a dielectric constant greater than one.

58. The open waveguide antenna of claim 57, wherein:

the upper outer surface of the dielectric cap has a longitudinal indent extending along the length of the slot.

59. The open waveguide antenna of claim 58, wherein:

the longitudinal indentation is centrally located along the length of the slot.

60. The open waveguide antenna of any one of claims 58-59, wherein: the longitudinal dimples have a concave cross-sectional profile.

61. The open waveguide antenna of claim 60, wherein:

the concave cross-sectional profile can be represented by a polynomial curve.

62. The open waveguide antenna of claim 57, wherein:

the upper outer surface of the dielectric cover has a longitudinal protrusion extending along the length of the slot.

63. The open waveguide antenna of claim 62, wherein:

The longitudinal projection is centrally disposed along the length of the slot.

64. The open waveguide antenna of any one of claims 62-63, wherein: the longitudinal projection has a convex cross-sectional profile.

65. The open waveguide antenna of claim 64, wherein:

The convex cross-sectional profile can be represented by a polynomial curve.

66. The open waveguide antenna of claim 57, wherein:

the lower inner surface of the dielectric cover has a longitudinal indent extending along the length of the slot.

67. The open waveguide antenna of claim 66, wherein:

the longitudinal indentation is centrally located along the length of the slot.

68. The open waveguide antenna of any one of claims 66-67, wherein: the longitudinal dimples have a concave cross-sectional profile.

69. The open waveguide antenna of claim 68, wherein:

the concave cross-sectional profile can be represented by a polynomial curve.

70. The open waveguide antenna of claim 57, wherein:

the lower inner surface of the dielectric cover has a longitudinal protrusion extending along the length of the slot.

71. The open waveguide antenna of claim 70, wherein:

The longitudinal projection is centrally disposed along the length of the slot.

72. The open waveguide antenna of any one of claims 70-71, wherein:

The longitudinal projection has a convex cross-sectional profile.

73. The open waveguide antenna of claim 72, wherein:

The convex cross-sectional profile can be represented by a polynomial curve.

74. The open waveguide antenna of any one of claims 42-73, having a moldable configuration, wherein:

The moldable configuration comprises one or more of the following: (i) Positive fabrication features that do not allow the planar surface features to stick during the barrel plating process; (ii) One or more screw locations incorporated into the construct; (iii) A drawn shell construction for reducing material consumption and warpage; (iv) An integrally formed recess for reducing sticking tendency during electroplating; (v) A mold draft angle of 2 degrees or more provided on the top side; (vi) A molding draft angle of 4 degrees or more provided on the bottom side; and (vii) a molded parting line located adjacent the bottom surface.

75. The open waveguide antenna of any one of claims 42-73, wherein:

The slot is of die-cast construction.

76. The open waveguide antenna of any one of claims 42-73, wherein:

The slot is of injection molded plastic construction.

77. The open waveguide antenna of claim 76, wherein:

the injection molded plastic construction is metallized to provide a conductive surface thereon.

78. An open waveguide antenna system comprising the open waveguide antenna of any one of claims 42-77, the open waveguide antenna system further comprising:

A signal feed port provided at one end of the slot; and

An electrical shorting circuit is provided at a second opposite end of the slot.

79. The open waveguide antenna system of claim 78, further comprising:

a conductive surface disposed near an upper end of the slot;

Wherein the electrical shorting circuit is electrically connected to the conductive surface; and

Wherein the conductive surface has an aperture configured and arranged to expose an upper end of the slot for electromagnetic coupling with the conductive surface.

80. The open waveguide antenna system of any one of claims 78-79, wherein:

The patch-to-slot guiding transition is configured such that the patch E polarization is parallel to the baffle.

81. The open waveguide antenna system of any one of claims 78-79, wherein:

the patch-to-slot guiding transition is configured such that the patch E polarization is perpendicular to the baffle.

82. A multi-channel open waveguide antenna comprising:

A plurality of open waveguide antennas according to any of claims 42 to 63 arranged in a side-by-side configuration with a center-to-center spacing of adjacent slots equal to or greater than λ/2 and equal to or less than 10 times λ, where λ is the wavelength at the operating frequency of the multi-channel open waveguide antenna.

83. The multi-channel open waveguide antenna of claim 82, wherein:

The side-by-side configuration is a multi-monomer construction.

84. The multi-channel open waveguide antenna of any one of claims 82-83, wherein:

the side-by-side configuration includes a plurality of receiver channels and a plurality of transmitter channels.

85. The multi-channel open waveguide antenna of claim 84, wherein:

The plurality of receiver channels includes at least 4 receiver channels.

86. The multi-channel open waveguide antenna of claim 84, wherein:

the plurality of transmitter channels includes at least 3 transmitter channels.

87. An open waveguide antenna system comprising:

a signal feed;

An EM transition portion, the EM transition portion comprising: a signal feed interface disposed at a first end of the EM transition portion and in EM communication with the signal feed, and an open waveguide section having a second end opposite the first end; and

An open waveguide antenna according to any one of claims 42 to 61, arranged for EM communication with the second end of the EM transition section;

Wherein the EM transition portion is configured to: coupling EM energy from the signal feed to the signal feed interface to a guided waveguide mode of EM energy, to the open waveguide section, and to the open waveguide antenna.

88. The open waveguide antenna system of claim 87, wherein:

The signal feed includes any one of the following: an in-package antenna; a circuit board structure; a patch; a signal probe; a signal loop; a signal aperture.

89. An open waveguide antenna system comprising:

packaging an antenna;

The open waveguide antenna of any one of claims 42 to 61;

And an EM transition disposed between and in EM signal communication with the on-package antenna and the open waveguide antenna.

90. The open waveguide antenna system of claim 89, wherein:

the EM transition includes a ridge waveguide.

91. The open waveguide antenna system of claim 89, wherein:

the EM transition includes a rectangular waveguide.

92. The open waveguide antenna system of claim 89, wherein:

the EM transition includes a waveguide bend.