CN112072286A

CN112072286A - Broadband PIFA antenna and communication terminal

Info

Publication number: CN112072286A
Application number: CN202010885426.5A
Authority: CN
Inventors: 姚坤
Original assignee: Realme Mobile Telecommunications Shenzhen Co Ltd
Current assignee: Realme Mobile Telecommunications Shenzhen Co Ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2020-12-11
Anticipated expiration: 2040-08-28
Also published as: CN112072286B

Abstract

The embodiment of the application discloses broadband PIFA antenna, includes: an antenna radiator, a first feed line and a second feed line, wherein: the antenna radiator comprises a first radiation branch, a second radiation branch and a third radiation branch which are respectively used for radiating energy of a first frequency band, a second frequency band and a third frequency band; a coupling gap exists between the second radiation branch and the third radiation branch, and is used for expanding the bandwidth corresponding to the third frequency band; the first feeder line connects the first radiating branch with a first feed point; the second feeder line is connected with the second radiation branch and the third radiation branch, one end of the second feeder line is connected with a feeding point, and the other end of the second feeder line is connected with a second feeding point. The embodiment of the application also provides a communication terminal.

Description

Broadband PIFA antenna and communication terminal

Technical Field

The present invention relates to the field of electronic device technology, and relates to but is not limited to a wideband PIFA (Planar Inverted-F antenna) antenna and a communication terminal.

Background

With the rapid development of wireless communication technology, the demand for intelligent terminals is increasing. As a core component of signal transceiving, an antenna plays an important role, and generally needs to have characteristics of small volume, wide coverage frequency band, and the like. In 5G (5th generation mobile networks, fifth generation mobile communication technology) mobile terminals, the working frequency band of the antenna reaches 5GHz (gigahertz). The conventional PIFA antenna has the problems of insufficient bandwidth and insufficient coverage.

Disclosure of Invention

The embodiment of the application aims to provide a broadband PIFA antenna and a communication terminal aiming at the problems of insufficient bandwidth and insufficient coverage of a PIFA antenna in a 5G mobile terminal in the prior art.

The technical scheme of the embodiment of the application is realized as follows:

in a first aspect, an embodiment of the present application provides a broadband PIFA antenna, where the PIFA antenna includes an antenna radiator, a first feed line, and a second feed line, where:

the antenna radiator comprises a first radiation branch, a second radiation branch and a third radiation branch which are respectively used for radiating energy of a first frequency band, a second frequency band and a third frequency band; a coupling gap exists between the second radiation branch and the third radiation branch, and is used for expanding the bandwidth corresponding to the third frequency band;

the first feeder line connects the first radiating branch with a first feed point;

the second feeder line is connected with the second radiation branch and the third radiation branch, one end of the second feeder line is connected with a feeding point, and the other end of the second feeder line is connected with a second feeding point.

In a second aspect, an embodiment of the present application provides a communication terminal, including a housing, a small plate, and the PIFA antenna of the embodiment of the present application, the PIFA antenna is located in the housing, and the PIFA antenna is fixedly connected to one side of the small plate.

The beneficial effects brought by the technical scheme provided by the embodiment of the application at least comprise:

the broadband PIFA antenna provided by the embodiment of the application comprises an antenna radiator, a first feeder line and a second feeder line, wherein the current on the antenna radiator can be redistributed by arranging coupling slots on a second radiation branch and a third radiation branch of the antenna radiator, so that the current length is changed, resonance in the working bandwidth is introduced, and the coverage of the PIFA antenna in multiple frequencies or wider frequency bands is realized by using smaller size. Under the conditions of not using a tuning switch, not increasing the wiring area and not increasing the antenna height, the simultaneous working of different antenna forms is realized through wiring optimization, the bandwidth of the PIFA antenna is greatly expanded, and a good communication function is realized.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic structural diagram of a broadband PIFA antenna provided in an embodiment of the present application;

fig. 2 is a schematic partial structural diagram of a communication terminal according to an embodiment of the present application;

fig. 3 is a schematic view of a current distribution of a PIFA antenna provided in an embodiment of the present application;

fig. 4 is a schematic view of a current distribution of a PIFA antenna provided in an embodiment of the present application;

fig. 5A is a schematic diagram of a PIFA antenna resonating within an operating bandwidth according to an embodiment of the present application;

fig. 5B is a schematic diagram of the total radiation efficiency of the PIFA antenna provided by the embodiment of the present application within the operating bandwidth;

fig. 6 is a schematic view of a radiation direction of a PIFA antenna provided by an embodiment of the present application at resonance within an operating bandwidth.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

It should be noted that the terms "first \ second \ third" referred to in the embodiments of the present application are only used for distinguishing similar objects and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may be interchanged under specific ordering or sequence if allowed, so that the embodiments of the present application described herein can be implemented in other orders than illustrated or described herein.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The use of the terms "vertical," "horizontal," "left," "right," and the like in the embodiments of the present application is for illustrative purposes only.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present application belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

With the rapid development of wireless communication technology, the demand for intelligent terminals is increasing. As a core component of signal transceiving, an antenna plays an important role, and generally needs to have characteristics of small volume, wide coverage frequency band, and the like.

With the advent of the 5G era, the current 5G smart terminal antenna basically needs to support a 5G communication frequency band (e.g., Sub6G, i.e., a frequency band with an operating frequency below 6G of 450GHz to 6000 GHz), and in order to meet the requirements of overseas operators, the terminal antenna basically needs to cover an N41 frequency band, i.e., a frequency range of 2515 to 2675GHz, an N78 frequency band, i.e., a frequency range of 3300 to 3800GHz, and an N79 frequency band, i.e., a frequency range of 4400 to 5000 GHz.

In a non-metal plastic rear case of a full-screen intelligent terminal, antennas made of a Flexible Printed Circuit (FPC) are mostly used, and a PIFA antenna is widely used in the above products due to its advantages of low cost, low profile, wide coverage frequency band, and the like. The PIFA antenna is named because the shape of the whole antenna is like the inverted english letter F. The basic structure of the antenna is that a plane radiation unit is used as a radiator, a large ground is used as a reflecting surface, and the radiator is provided with two pins (Pin pins) which are close to each other and are respectively used for grounding and serving as feed points.

The bandwidth of the PIFA antenna has a high requirement on the height of the antenna, most of the conventional ultrathin intelligent antennas have a thickness of less than 10 millimeters (mm), and particularly, the plastic rear shell is ultrathin, so that the antenna design of the intelligent terminal faces huge challenges under the condition of considering performance, cost and working bandwidth, and compared with the conventional antenna which does not support a 5G communication frequency band, the working bandwidth of the conventional antenna of the intelligent terminal is urgently required to be expanded.

The embodiment of the present application provides a broadband PIFA antenna, and fig. 1 is a schematic structural diagram of the broadband PIFA antenna provided in the embodiment of the present application, and as shown in fig. 1, the PIFA antenna 10 includes an antenna radiator 11, a first feeder 12, and a second feeder 13, where:

the antenna radiator 11 includes a first radiation branch 111, a second radiation branch 112, and a third radiation branch 113 for radiating energy of a first frequency band, a second frequency band, and a third frequency band, respectively.

The antenna radiator 11 has three inherent basic resonances, namely, a first frequency band, a second frequency band and a third frequency band, wherein the first frequency band, the third frequency band and the second frequency band are sequentially a high frequency, a medium frequency and a low frequency, and are respectively generated by the first radiation branch 111, the second radiation branch 112 and the third radiation branch 113. Wherein the first radiating branch 111 extends from the first feed line 12, and the second radiating branch 112 and the third radiating branch 113 both extend from the second feed line 13.

A coupling gap 14 exists between the second radiating branch 112 and the third radiating branch 113, and is used for expanding a bandwidth corresponding to the third frequency band.

It should be noted that the coupling slot 14 is obtained by slotting the antenna radiator 11. The coupling slot 14 may redistribute the current on the antenna radiator 11 and thereby change the current length. Therefore, the antenna radiator 11 can implement impedance matching at a higher frequency point, i.e., a third frequency band, so as to introduce a new intermediate frequency resonance, thereby expanding the bandwidth of the corresponding frequency point. That is, by opening the coupling slot 14, the impedance bandwidth of the PIFA antenna 10 can be further widened on the original basis. The specific frequency value of the intermediate frequency resonance point can be adjusted by adjusting the length, width and position of the coupling slot 14.

It should be noted that the application of the coupling gap 14 between the second radiating branch 112 and the third radiating branch 113 provided in the embodiment of the present application to expand the bandwidth of the third frequency band, i.e. the intermediate frequency, is only a preferred embodiment, and in other possible embodiments, the bandwidth of other frequency bands may also be expanded. The method is not particularly limited and may be determined according to actual conditions.

Said first feed line 12 connecting said first radiating branch 111 with a first feed point 15; the second feeding line 13 is connected to the second radiation branch 112 and the third radiation branch 113, one end of the second feeding line 13 is connected to the feeding point 16, and the other end of the second feeding line 13 is connected to the second feeding point 17.

The first feeder 12 and the second feeder 13 may be microstrip lines connecting the feed source and the radiating element, but are not limited to microstrip lines, and may also be elastic pins, and the like as connecting lines for signal transmission. For example, after energy enters the feeding point 16, the energy of the corresponding frequency band is radiated out through the three branches of the antenna radiator 11 through the first feeding line 12 and the second feeding line 13, respectively.

The first feed line 12 and the second feed line 13 may take the form of coaxial lines or any other suitable form in practice. The arrangement of the first feeder line 12 and the second feeder line 13 is not limited herein, and may be determined according to actual situations.

In some possible embodiments, the first radiating branch 111 also serves as a parasitic element for generating a resonance operating in the first frequency band.

When the antenna radiator 11 radiates electromagnetic waves, the electromagnetic waves can be coupled to the first radiation branch 111, so that the first radiation branch 111 can generate higher-frequency resonance, that is, a new high-frequency resonance point is introduced, and impedance matching can be achieved at higher frequency points. Wherein the frequency of the high-frequency resonance point is higher than that of the medium-frequency resonance point. That is, by setting the first radiation branch as a parasitic element, the impedance bandwidth of the PIFA antenna 10 is further widened on the original basis. Due to the coupling slot 14 and the parasitic element, the antenna radiator 11 can achieve coverage of multiple frequencies or wider frequency bands with a smaller size.

In some possible embodiments, by properly processing the slot position and the slot position on the PIFA antenna 10 trace, when the antenna radiator 11 receives an electromagnetic wave signal, the generated current forms a loop current path through the coupling slot 14, that is, a loop current distribution is generated between the second radiation branch 112 and the third radiation branch 113, so as to add an additional loop current mode, thereby generating resonance and expanding the antenna bandwidth.

In some possible embodiments, the size of the coupling slot 14 is determined according to the frequency size of the third frequency band. That is to say, the loop current distribution formed by the slot and the slot in the embodiment of the present application is not unique, and can be adjusted accordingly according to the actual antenna frequency band requirement.

In some possible embodiments, the third radiating branch 113 includes a first radiating arm with adjustable length and a second radiating arm connected to the first radiating arm.

In some possible embodiments, the length of the coupling slot 14 is adjusted by adjusting the length of the first radiating arm.

In some possible embodiments, the PIFA antenna 10 operates in a New Radio (NR) 5G frequency band, the first frequency band is an N79 frequency band (frequency range from 4600GHz to 5000GHz), the second frequency band is an N1 frequency band (frequency range from 1920GHz to 2170GHz), and the third frequency band is an N78 frequency band (frequency range from 3300GHz to 3800 GHz).

In some possible embodiments, the second radiating branch 112 and the third radiating branch 113 are both L-shaped traces, and an end of the second radiating branch 112 close to the second feeding line 13 is narrower than a trace at an end of the second radiating branch 112.

Here the end position of the second radiating branch 112 is at the top of the support of the PIFA antenna 10 (not shown in fig. 1), the wider trace patch favours antenna radiation; the second radiation branch 112 is implemented by adopting a narrower trace near the feeder line, on one hand, the narrower antenna trace can reduce the coupling with the same-end wide trace portion, such as the third radiation branch, and reduce the negative influence on the antenna radiation, on the other hand, the narrow trace has stronger sensitivity, and the occupied volume of the antenna is further reduced.

In some possible embodiments, the routing design of the PIFA antenna 10 is implemented by a flexible FPC. That is, the PIFA antenna 10 is a miniaturized FPC antenna, and the routing design of the antenna is implemented by attaching an FPC to the inside of a plastic back cover.

Fig. 2 is a schematic partial structural diagram of a communication terminal according to an embodiment of the present application, which may be any network terminal including a PIFA antenna, such as a Wireless router, a portable Wireless Fidelity (Wi-Fi) hotspot transmitter, and as shown in fig. 2, the communication terminal 20 includes a housing 21, a small plate 22, and the PIFA antenna 10.

The PIFA antenna 10 is a wide band antenna in the above embodiments, and is located in the housing 21, and the PIFA antenna 10 is fixedly connected to one side of the small plate 22. And the signal transceiving function of the communication terminal and the outside is realized.

The housing 21 is generally made of non-metal material such as ABS (Acrylonitrile Butadiene Styrene) or PC (Poly Carbonate).

The small board 22 is used as a charging interface and is generally connected to a USB module or an earphone module in the communication terminal 20.

The resonance principle of the PIFA antenna provided in the embodiment of the present application is analyzed below. The formation of circulating currents can be observed by the current distribution on the antenna.

Fig. 3 is a schematic view of current distribution of a PIFA antenna provided by an embodiment of the present application, and the pointing direction and distribution density of the arrows in fig. 3 represent the direction and intensity of the antenna surface current, respectively, wherein the black arrows indicate the portions indicating that the current distribution density is relatively large.

As shown in part a of fig. 3, which represents the current distribution on the antenna radiator for a frequency of 2.0GHz, it can be seen that the current on the path of the second radiating branch 112 is stronger when the frequency is within the N1 band.

As shown in parts B and C of fig. 3, which respectively represent current distributions on the antenna radiators corresponding to frequencies of 3.3GHz and 3.67GHz, it can be seen that when the frequency is within the N78 frequency band, in addition to a stronger current distribution on the third radiation branch 113, there is a stronger annular current distribution between the second radiation branch 112 and the third radiation branch 113, as shown by the black arrow part in fig. 3. That is, in addition to the energy of the N78 band radiated by the third radiating branch, another resonance operating in the N78 band is generated in the gap region between the second radiating branch 112 and the third radiating branch 113.

As shown in part D of fig. 3, which shows the current distribution on the antenna radiator for a frequency of 4.76GHz, it can be seen that the current mainly flows through the path of the first radiating branch 111 when the frequency is in the N79 frequency band. Thus, the N79 resonance is generated by the first radiating branch 111.

Meanwhile, the distribution condition of the electric field on the surface of the PIFA antenna can be observed, and the working principle of the PIFA antenna can be further observed.

Fig. 4 is a schematic diagram of current distribution of a PIFA antenna according to an embodiment of the present application, and as shown in fig. 4, portions A, B, C, D are electric field distribution diagrams at frequencies of 2GHz, 3.3GHz, 3.67GHz, and 4.76GHz, respectively. The darker the color of the shaded portion in fig. 4 represents the stronger the radiation there. The radiation on the second radiation branch 112 is stronger as shown in part a of fig. 4; parts B and C show that the radiation in the region of the annular distribution between the second radiating branch 112 and the third radiating branch 113 is stronger, i.e. the bandwidth of N78 is expanded by adding the coupling slot 14 to generate an additional circular current mode; section D shows the first radiating branch 111 as a parasitic element, the radiation on this path being strong, indicating that resonance in the N79 band is generated.

Fig. 5A is a schematic diagram of the resonance of the PIFA antenna provided by the embodiment of the present application in the operating bandwidth, as shown in fig. 5, where the horizontal axis represents frequency and the vertical axis represents radiated energy, and in fig. 5, a trough appears at every other frequency range, which represents that a resonance is generated in the corresponding frequency range. It can be seen that there is only one resonance between frequency point 51 and frequency point 52 (frequency range is 1.92GHz to 2.17GHz, corresponding to the N1 frequency band) and between frequency point 55 and frequency point 56 (frequency range is 4.6GHz to 5GHz, corresponding to the N79 frequency band), while there are two resonances between frequency point 53 and frequency point 54 (frequency range is 3.3GHz to 3.8GHz, corresponding to the N78 frequency band). That is, the PIFA antenna generates two resonances within the N78 bandwidth, effectively expanding the bandwidth of the PIFA antenna.

Fig. 5B is a schematic diagram of the total radiation efficiency of the PIFA antenna provided by the embodiment of the present application within the operating bandwidth. As shown in fig. 5B, PIFA antenna 10 has total radiation efficiencies of-3.5 dB, -3.2dB, and-4.3 dB in the N1 band, the N78 band, and the N79 band, respectively.

Fig. 6 is a schematic view of the radiation direction of the PIFA antenna provided in the embodiment of the present application at resonance within the operating bandwidth, and as shown in fig. 6, the radiation direction of PIFA antenna 10 is good in the two-dimensional direction where the horizontal plane θ is 90 °. At four frequency points of 2GHz, 3.3GHz, 3.67GHz and 4.76GHz, the corresponding gains are 5.4dBi, 6.4dBi, 3.53dBi and 5.91dBi respectively.

By observing the patterns at resonance within the three operating bandwidths of N1, N78, and N79, the antenna maintains good radiation directivity characteristics within the operating bandwidth. That is, the PIFA antenna 10 completely covers the N1, N78, and N79 bands of 5G, has good radiation characteristics at the operating frequency of each communication system, substantially maintains omni-directionality, and completely meets the requirement of omnidirectional radiation of the antenna.

According to the broadband PIFA antenna provided by the embodiment of the application, the coupling slot is designed in the antenna radiating body, the current distribution in the antenna radiating body is changed, the resonance in the working bandwidth is introduced by adding an additional circulating current mode, and the coverage of the PIFA antenna in multiple frequencies or wider frequency bands is realized by using a smaller size. Under the conditions of not using a tuning switch, not increasing the wiring area and not increasing the height of the PIFA antenna, the simultaneous working of different PIFA antenna forms is realized through wiring optimization, the bandwidth of the PIFA antenna is greatly expanded, and a good communication function is realized.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application. The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between the devices or units may be electrical, mechanical or other forms.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units; can be located in one place or distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present application.

In addition, all functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above description is only for the embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A broadband PIFA antenna comprising an antenna radiator, a first feed line and a second feed line, wherein:

2. The PIFA antenna of claim 1, wherein said first radiating branch also acts as a parasitic element for generating resonance operating in said first frequency band.

3. The PIFA antenna of claim 1, wherein a current generated by said antenna radiator when receiving an electromagnetic wave signal forms a circulating current path through said coupling slot.

4. The PIFA antenna of claim 3, wherein said coupling slot is sized according to the frequency size of said third band.

5. The PIFA antenna of claim 1, wherein said third radiating branch includes a first radiating arm having an adjustable length and a second radiating arm connected to said first radiating arm.

6. The PIFA antenna of claim 5, wherein the length of said coupling slot is adjusted by adjusting the length of said first radiating arm.

7. The PIFA antenna according to any of claims 1 to 6, wherein the first frequency band is the N79 frequency band, the second frequency band is the N1 frequency band, and the third frequency band is the N78 frequency band.

8. The PIFA antenna of claim 1, wherein the second radiating branch and the third radiating branch are both L-shaped traces, and wherein an end of the second radiating branch proximate to the second feed line is narrower than the trace at the end of the second radiating branch.

9. The PIFA antenna of claim 1, wherein the PIFA antenna trace design is implemented by a flexible circuit board, FPC.

10. A communication terminal comprising a housing, a platelet and a PIFA antenna as claimed in any one of claims 1 to 9, the PIFA antenna being located within the housing and fixedly connected to one side of the platelet.