CN117673762A - Frequency selective surface and spatial filtering method - Google Patents
Frequency selective surface and spatial filtering method Download PDFInfo
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- CN117673762A CN117673762A CN202211021650.5A CN202211021650A CN117673762A CN 117673762 A CN117673762 A CN 117673762A CN 202211021650 A CN202211021650 A CN 202211021650A CN 117673762 A CN117673762 A CN 117673762A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
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Abstract
The embodiment of the invention provides a frequency selective surface and a spatial filtering method, which comprises the following steps of: a first surface formed of a plurality of first metal strips interlaced with each other; the second surface is formed by a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, the metal strips on two sides of the second inter-strip gap are connected through metal strip wires to form a parallel resonance LC circuit in an H frequency band, and the first surface and the second surface are fixed on the same side or front and back sides of the support plate. The problem that a 4G passive antenna cannot be perfectly fused with a 5G active antenna in the related art is solved.
Description
Technical Field
The embodiment of the invention relates to the field of communication, in particular to a frequency selective surface and a spatial filtering method.
Background
The 5G active antenna deployment faces three major challenges: 1. the sites cannot be newly added; 2. the existing site can not additionally deploy a 5G active antenna by deploying a 4G passive antenna; 3. existing sites can additionally deploy 5G active antenna facets, but the hanging height is limited and optimal signal coverage cannot be obtained. For this purpose, a fusion scheme of 4G passive antenna and 5G active antenna, a+p (Active plus Passive, a+p) antenna, was proposed. The A+P antenna is a multi-frequency common-caliber antenna, and a 5G active antenna is embedded into a 4G passive antenna from the back by adopting an integrated interweaving scheme, so that integrated deployment is realized. The performance of the A+P antenna can be aligned with the existing network, the separate maintenance and independent deployment of the active antenna and the passive antenna are supported, the operation cost can be greatly reduced, and the requirements of smooth upgrading of equipment are met.
To meet the a+p antenna performance, a frequency selective surface (Frequency Selecitve Surface, FSS) needs to be designed to achieve perfect integration of passive and active antennas.
Disclosure of Invention
The embodiment of the invention provides a frequency selective surface and spatial filtering method, which at least solves the problem that a 4G passive antenna cannot be perfectly fused with a 5G active antenna in the related technology.
According to an embodiment of the present invention, there is provided a frequency selective surface unit including: a first surface formed of a plurality of first metal strips interlaced with each other; the second surface is formed by a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, and the metal strips on two sides of the second inter-strip gap are connected through metal strip wires so as to form a parallel resonance LC circuit in an H frequency band; the first surface and the second surface are fixed on the same side or front and back surfaces of the supporting plate.
In an exemplary embodiment, first inter-band gaps are distributed at both ends of each of the first metal strips, and the second inter-band gaps are located in a preset area above or below the first inter-band gaps in a state that the first surface and the second surface are fixed to the front and back surfaces of the support plate, so that a series resonant LC circuit is formed in an L frequency band.
In one exemplary embodiment, the first metal strip further comprises: the metal strip comprises a first central metal strip and two first side metal strips, wherein the first central metal strip is positioned in the middle of the first metal strip, the two first side metal strips are respectively distributed at two ends of the first metal strip, and a first inter-strip gap is formed between each first side metal strip and the first central metal strip.
In one exemplary embodiment, the second metal strip further includes: and the two second side end metal strips are distributed on two sides of the second inter-belt gap and are connected through the metal belt wires.
In an exemplary embodiment, the second inter-band gap is located in a preset area above or below the first inter-band gap to form a series resonant LC circuit in an L-band, including: the first center metal strip, the two first side metal strips, the two second side metal strips and the metal strip line are connected in series to form a series resonance LC circuit in the L frequency band.
In one exemplary embodiment, the first metal strip and/or the second metal strip is at least one of: an elongated metal strap wire; bending the metal strap wire; a metal coil; and (5) a metal via.
In an exemplary embodiment, the first metal strip and the second metal strip are connected in one of the following ways: the coplanar coupling lines are connected; non-coplanar coupling line connections; the interlaced wires are connected.
In one exemplary embodiment, the support plate is one of: a dielectric substrate; a ceramic; a sheet metal strip line; a metal body.
According to a further embodiment of the present invention, there is also provided a frequency selective surface, consisting of the above frequency selective surface element period extension.
In an exemplary embodiment, the frequency selective surface comprises one of: -said frequency selective surface element of single layer period extension; said frequency selective surface element of a dual layer period extension; the frequency selective surface unit of multi-layer period extension.
According to a further embodiment of the present invention, there is also provided a spatial filtering method, characterized by being implemented with the frequency selective surface of claim 10, comprising: and adjusting the L value or the C value of the series resonant LC circuit and the parallel resonant LC circuit to control the transmission frequency band and the reflection frequency band of the frequency selective surface unit.
In one exemplary embodiment, further comprising: the number of the series resonant LC circuits and the parallel resonant LC circuits are adjusted to control the transmission bandwidth and the reflection bandwidth of the frequency selective surface unit.
With the above-described embodiments of the present invention, by providing a frequency selective surface unit comprising: a first surface formed of a plurality of first metal strips interlaced with each other; the second surface is formed by a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, and the metal strips on two sides of the second inter-strip gap are connected through metal strip wires so as to form a parallel resonance LC circuit in an H frequency band; the first surface and the second surface are fixed on the same side or the front side and the back side of the supporting plate. The problem that a 4G passive antenna cannot be perfectly fused with a 5G active antenna in the related art is solved.
Drawings
Fig. 1 is a schematic diagram of an FSS-based a+p antenna scheme in accordance with an embodiment of the present invention;
fig. 2 is a block diagram of a frequency selective surface unit according to an embodiment of the present invention;
FIG. 3 is a block diagram of a first metal strip of a first surface according to an embodiment of the present invention;
FIG. 4 is a block diagram of a second metal strip of a second surface according to an embodiment of the present invention;
FIG. 5 is a flow chart of a spatial filtering method according to an embodiment of the invention;
FIG. 6 is a flow chart of a spatial filtering method according to an embodiment of the invention;
FIG. 7 is a schematic diagram of the structure of the upper and lower surfaces of an FSS unit according to an embodiment of the present invention;
FIG. 8 is a perspective side view of an FSS unit according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of the structure of the upper surface of the FSS according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of the structure of the lower surface of the FSS according to an embodiment of the present invention;
FIG. 11 is a schematic diagram of a fourth order series-parallel resonant circuit construction in accordance with an embodiment of the inventive arrangements;
FIG. 12 is a schematic diagram of FSS cell shapes according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of a multi-layer FSS structure according to an embodiment of the present invention;
FIG. 14 is a schematic diagram of a distributed LC circuit architecture according to an embodiment of the present invention;
FIG. 15 is a schematic diagram of a distributed LC circuit architecture according to an embodiment of the present invention;
FIG. 16 is a schematic diagram of a distributed LC circuit architecture according to an embodiment of the present invention;
FIG. 17 is a schematic diagram of a distributed LC circuit architecture according to an embodiment of the present invention;
FIG. 18 is a schematic diagram of a distributed LC circuit architecture according to an embodiment of the present invention;
FIG. 19 is a schematic diagram of an FSS cell structure according to an embodiment of the present invention;
FIG. 20 is a schematic diagram of an FSS cell structure according to an embodiment of the present invention;
FIG. 21 is a schematic diagram of an FSS cell structure according to an embodiment of the present invention;
fig. 22 is a schematic diagram of an FSS unit architecture according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings in conjunction with the embodiments.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.
The A+P antenna is a multi-frequency common-caliber antenna, and a 5G active antenna is embedded into a 4G passive antenna from the back by adopting an integrated interweaving scheme, so that integrated deployment is realized. The performance of the A+P antenna can be aligned with the existing network, the separate maintenance and independent deployment of the active antenna and the passive antenna are supported, the operation cost can be greatly reduced, and the requirements of smooth upgrading of equipment are met.
The frequency selective surface (Frequency Selecitve Surface, FSS) is a periodic artificial electromagnetic material that can regulate electromagnetic waves of a specific frequency or polarization. By utilizing the FSS filtering function of the space electromagnetic wave, the reflection of the low-frequency signals (690-960 MHz, L frequency band) and the transmission of the high-frequency signals (2490-2690 MHz or 3400-3800MHz, H frequency band) can be realized. FSS technology can meet the development requirement of A+P products, and perfect integration of passive and active antenna surfaces is realized.
Fig. 1 is a schematic diagram of an a+p antenna scheme based on FSS, and as shown in fig. 1, from top to bottom, are a passive antenna operating in the L frequency band, FSS, and an active antenna operating in the H frequency band, respectively. FSS has low-resistance high-pass characteristic to space electromagnetic wave, and can be used as a reflecting plate of a passive antenna and an antenna housing of an active antenna. Meanwhile, the FSS spatial filtering function can reduce different frequency coupling between the L and H frequency band antennas and improve the antenna performance. Finally, the A+P antenna based on FSS can ensure the independence of the 4G passive antenna and the 5G active antenna, namely, the independent design, independent deployment and independent maintenance of the active antenna and the passive antenna are supported.
In this embodiment, a frequency selective surface unit is provided, fig. 2 is a block diagram of a frequency selective surface unit according to an embodiment of the present invention, and as shown in fig. 2, the frequency selective surface unit 20 includes: a first surface 210 formed of a plurality of first metal strips interlaced with each other; the second surface 220 is formed by a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, and the second metal strips on two sides of the second inter-strip gap are connected through metal strips so as to form a parallel resonance LC circuit in an H frequency band; the support plate 230, wherein the first surface 210 and the second surface 220 may be fixed to the same side or opposite sides of the support plate 230.
In the frequency selective surface unit provided in the above embodiment of the present invention, the first surface is constituted by a plurality of first metal strips that are interlaced with each other; the second surface comprises a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, the metal strips on two sides of each second inter-strip gap are connected through metal strips so as to form a parallel resonance LC circuit in an H frequency band, and the first surface and the second surface are fixed on the same side or the front side and the back side of the supporting plate, so that the problem that a 4G passive antenna cannot be perfectly fused with a 5G active antenna in the related art is solved.
In one exemplary embodiment, first inter-band gaps are distributed at both ends of each first metal strip, and the second inter-band gaps are located in a predetermined region above or below the first inter-band gaps in a state that the first surface and the second surface are fixed to the front and rear surfaces of the support plate to constitute a series resonant LC circuit in the L frequency band.
In the embodiment of the invention, the first inter-band gaps may be symmetrically distributed at two ends of the first metal strip, and the second inter-band gaps may be located directly under the first inter-band gaps, where the positional relationship between the second inter-band gaps and the first inter-band gaps is not specifically limited, i.e., the positional relationship between the first surface and the second surface is not limited, and the second surface may be located directly under the first surface or directly above the first surface, and the second surface may be located in the same layer as the first surface and distributed on the left side, the right side, and the like of the first surface. The scheme that the second surface and the first surface are in the same layer is merely a change of a positional relationship, and the specific connection relationship and the spatial coupling relationship may be the same as those when the second surface is located directly under the first surface, that is, a serial-parallel connection manner of forming a parallel resonant LC circuit and a serial resonant LC circuit between the elements is the same, which will not be described herein.
In one exemplary embodiment, fig. 3 is a block diagram of a first metal strip of a first surface according to an embodiment of the present invention, as shown in fig. 3, the first metal strip 30 further comprising: the first central metal strip 310 and the two first side metal strips 320, wherein the first central metal strip 310 is located in the middle of the first metal strip 30, the two first side metal strips 320 are respectively distributed at two ends of the first metal strip 30, and a first inter-strip gap is formed between each first side metal strip 320 and the first central metal strip 310.
In one exemplary embodiment, fig. 4 is a block diagram of a second metal strip of a second surface according to an embodiment of the present invention, as shown in fig. 4, the second metal strip 40 further comprising: two second side end metal strips 410, wherein the two second side end metal strips 410 are distributed on two sides of the second inter-strip gap and are connected by metal strip lines 420.
In one exemplary embodiment, the second inter-band gap is located in a preset region above or below the first inter-band gap to form a series resonant LC circuit in the L frequency band, comprising: the first center metal strip 310, the two first side metal strips 320, the two second side metal strips 410, and the metal strip line 420 are connected in series to constitute a series resonant LC circuit in the L-band.
In one exemplary embodiment, the first metallic strip 30 and/or the second metallic strip 40 is at least one of: an elongated metal strap wire; bending the metal strap wire; a metal coil; and (5) a metal via. Wherein, in the embodiment of the invention, the slender metal belt line refers to a metal belt line with the length being more than or equal to 5 times of the width.
In one exemplary embodiment, the first metal strip 30 and the second metal strip 40 are connected in one of the following ways: the coplanar coupling lines are connected; non-coplanar coupling line connections; the interlaced wires are connected.
In one exemplary embodiment, the support plate is one of: a dielectric substrate; a ceramic; a sheet metal strip line; a metal body.
According to another embodiment of the present invention, a frequency selective surface is provided, which is formed by the above-mentioned frequency selective surface element period extension.
In one exemplary embodiment, the frequency selective surface is one of: frequency selective surface elements with single layer period extension; a frequency selective surface element of a dual-layer period extension; frequency selective surface elements of multi-layer period extension.
According to still another embodiment of the present invention, there is provided a spatial filtering method implemented using the above-mentioned frequency selective surface, and fig. 5 is a flowchart of the spatial filtering method according to an embodiment of the present invention, as shown in fig. 5, the flowchart including the steps of:
in step S502, the L value or the C value of the series resonant LC circuit and the parallel resonant LC circuit are adjusted to control the transmission frequency band and the reflection frequency band of the frequency selective surface unit.
In an exemplary embodiment, fig. 6 is a flowchart of a spatial filtering method according to an embodiment of the present invention, as shown in fig. 6, the flowchart including the steps of:
step S602, adjusting L value or C value of the series resonant LC circuit and the parallel resonant LC circuit to control transmission frequency band and reflection frequency band of the frequency selective surface unit;
in step S604, the number of the series resonant LC circuits and the parallel resonant LC circuits is adjusted to control the transmission bandwidth and the reflection bandwidth of the frequency selective surface unit.
It should be appreciated by those skilled in the art that the order of execution among the steps may be interchanged, and the present invention is not limited thereto.
In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following description is provided with reference to specific exemplary embodiments. In an embodiment of the present invention, the upper surface is the first surface, and the lower surface is the second surface.
Scene embodiment one
In this embodiment of the present scenario, a low-resistance high-pass FSS is provided.
Fig. 7 is a schematic view of the structure of the upper and lower surfaces of the FSS unit according to the embodiment of the present invention, as shown in fig. 7, in which the FSS unit includes an upper surface 1, a dielectric substrate 2, and a lower surface 3, and the dielectric substrate 2 supports the upper surface 1 and the lower surface 3. Wherein, the upper surface 1 is formed by two first metal strips 11 orthogonal to each other, and the first metal strips 11 sequentially comprise a first center metal strip 111 and a first side metal strip 112 from the center to the outside. The lower surface 3 is formed by four second metal strips 31 rotating, the second metal strips 31 comprising second side end metal strips 311, 313 and a second central metal strip 312. The second metal strip 31 is located directly below the gap between the first center metal strip 111 and the first side metal strip 112, i.e., as shown in fig. 7, the gap between the second side metal strips 311, 313 is aligned with the gap between the first center metal strip 111 and the first side metal strip 112.
Fig. 8 is a side view of a perspective structure of an FSS unit according to an embodiment of the present invention. It should be noted that, in the present embodiment, the second metal strip 31 is located directly below the gap between the first center metal strip 111 and the first side metal strip 112 for realizing the positional relationship that the lower surface is located directly below the upper surface, but the upper surface and the lower surface are not limited to this positional relationship.
The second central metal strip 312 has a width much smaller than the length, which may be equivalent to an inductance, for example, in this embodiment, the much smaller range may be a length of the metal strip greater than or equal to 5 times the width; the coupling connection between the second side metal strips 311, 313 may be equivalently a capacitor. The second center metal strip 312 and the second side end metal strips 311 and 313 are in parallel connection, and can form a parallel resonance LC circuit in the H frequency band.
The second side end metal strips 311 and 313 are respectively coupled with the first central metal strip 111 and the first side end metal strip 112, and can be equivalently used as capacitors; the first center metal strip 111, the first side end metal strip 112, and the second center metal strip 312 may be equivalent to an inductance. The first center metal strip 111, the first side end metal strip 112, the second side end metal strips 311, 313, and the second center metal strip 312 are in a series state, and a series resonant LC circuit can be formed in the L frequency band.
Fig. 9 is a schematic diagram of the structure of the upper surface of the FSS according to the embodiment of the present invention, and fig. 10 is a schematic diagram of the structure of the lower surface of the FSS according to the embodiment of the present invention, as shown in fig. 9 and 10, the FSS is composed of the FSS cell cycle extension shown in fig. 7.
H frequency band, the parallel resonance LC circuit is opened to generate a reflection zero point, so that electromagnetic wave transmission is realized; l frequency band, the transmission zero point is generated by the short circuit of the series LC circuit, and the electromagnetic wave reflection is realized.
Fig. 11 is a schematic diagram of a fourth-order series-parallel resonant circuit construction according to an embodiment of the present invention, and as shown in fig. 11, a first-order, a second-order, or a multi-order series-parallel resonant circuit can be constructed by increasing the number of metal strips 11.
FIG. 12 is a schematic diagram of the shape of an FSS cell, which is rectangular as shown in FIG. 12, according to an embodiment of the present invention. It should be appreciated by those skilled in the art that the FSS unit provided by the present invention may be square, rectangular, triangular, polygonal, and the shape is not limited herein.
Fig. 13 is a schematic diagram of a multi-layered FSS structure according to an embodiment of the present invention, and as shown in fig. 13, the FSS may be a single-layered structure, a two-layered structure, or a multi-layered structure.
Scene embodiment two
The FSS provided by the invention realizes the spatial filtering of low-resistance high-pass characteristics by designing an L-band series LC circuit and an H-band parallel LC circuit. The series/parallel LC circuit and the equivalent capacitive inductance element are not limited to the form described in the first embodiment of the scenario, for example, the inductance may be designed as an elongated straight line, a bent line, a coil, a metal via hole, or the like; the capacitors may be designed as coplanar coupled lines, non-coplanar coupled lines, interleaved lines, etc. Several examples of structures of series-parallel LC circuits are given below, but are described herein by way of example only and are not used as specific limitations.
Fig. 14 is a schematic diagram of a distributed LC circuit according to an embodiment of the present invention, as shown in fig. 14, including upper and lower metal strips, where the coupling regions of the upper and lower metal strips are equivalent to capacitors, and the upper metal strip is equivalent to an inductor. The structure can be seen as a series LC circuit, which can provide an L-band transmission zero.
FIG. 15 is a schematic diagram of a distributed LC circuit according to an embodiment of the present invention, as shown in FIG. 15, including a single metal strip line, a thin line bent in the middle being equivalent to an inductor, and wide lines on both sides being equivalent to a capacitor (note that the capacitor may be small, and the corresponding line width is thin); this structure can be regarded as a parallel LC circuit, which can provide an H-band reflection zero.
FIG. 16 is a schematic diagram of a distributed LC circuit according to an embodiment of the present invention, as shown in FIG. 16, comprising upper and lower metal strips, wherein the middle bent thin line of the lower metal strip is equivalent to an inductor, and the metal strips on two sides of the thin line are equivalent to a capacitor, and the two metal strips form a parallel LC circuit; the upper metal strap and the lower metal strap coupling region are equivalent to a capacitor, and the upper metal strap is equivalent to an inductor. The structure can be regarded as a parallel LC circuit and a serial LC circuit, and can provide an L-band transmission zero point and an H-band reflection zero point.
FIG. 17 is a schematic diagram of a distributed LC circuit according to an embodiment of the present invention, as shown in FIG. 17, comprising upper and lower metal strips, wherein the bent thin line at the side of the lower metal strip is equivalent to an inductor, and the metal strip at the two sides of the wide seam is equivalent to a capacitor, and the two metal strips form a parallel LC circuit; the upper metal strap and the lower metal strap coupling region are equivalent to a capacitor, and the upper metal strap is equivalent to an inductor. The structure can be regarded as a parallel LC circuit and a serial LC circuit, and can provide an L-band transmission zero point and an H-band reflection zero point.
Fig. 18 is a schematic diagram of a distributed LC circuit according to an embodiment of the present invention, as shown in fig. 18, including a single metal strip, two side 1/4 wavelength open stubs each forming an equivalent inductance, and two stubs coupled with an intermediate metal strip forming an equivalent capacitance. This structure can be regarded as a parallel LC circuit, which can provide an H-band reflection zero.
It should be appreciated by those skilled in the art that the distributed LC circuit structure provided above may be used to replace overlapping portions of projections of metal lines or strips on the upper and lower surfaces of the FSS cell in a direction perpendicular to the dielectric substrate.
Scene embodiment III
The embodiment of the scene provides a spatial filtering method. The parallel LC resonance circuit and the series LC resonance circuit can change resonance frequency by adjusting L value or C value, thereby controlling transmission frequency band and reflection frequency band; n series resonant circuits and M parallel resonant circuits (N, M is greater than or equal to 1) are constructed, and increasing the value of N or M can increase the transmission bandwidth and the reflection bandwidth respectively.
Fig. 19 is a schematic structural diagram of an FSS unit according to an embodiment of the present invention, where, as shown in fig. 19, each of two orthogonal metal strips of the FSS unit has 4 parallel LC circuits and 2 series LC circuits, and may provide reflection zeros in 4H frequency bands and transmission zeros in 2L frequency bands.
Scene example four
Fig. 20 is a schematic structural diagram of an FSS unit according to an embodiment of the present invention, where, as shown in fig. 20, each of two orthogonal metal strips of the FSS unit has 4 parallel LC circuits and 2 series LC circuits, and may provide reflection zeros in 4H frequency bands and transmission zeros in 2L frequency bands. The parallel LC circuit is composed of a bending inductance line and thin lines at two ends, and the thin lines at two ends have smaller width and smaller capacitance value, and the parallel LC circuit is similar to a pure inductance but still belongs to the parallel LC circuit in a strict sense.
Fig. 21 is a schematic diagram of an FSS unit structure according to an embodiment of the present invention, and fig. 22 is a schematic diagram of an FSS unit structure according to an embodiment of the present invention.
According to the structure schematic diagrams of the FSS unit provided in the above embodiment of the scenario, those skilled in the art should appreciate that the FSS provided in the present invention has various implementation structures.
According to the invention, on a periodic metal strip, the functions of L-band electromagnetic wave reflection and H-band electromagnetic wave transmission are realized by constructing a distributed LC circuit with a series resonance characteristic in the L-band and a parallel resonance characteristic in the H-band, and respectively creating a transmission zero and a reflection zero in the L-band and the H-band. By utilizing the method, not only the low-resistance high-pass filtering function of the space electromagnetic wave can be obtained, but also electromagnetic scattering of the H frequency band can be restrained, and the antenna working in the H frequency band can be ensured to obtain an excellent radiation pattern conformal effect.
In summary, the FSS provided by the invention has the following characteristics: 1) The material can be applied to different carrier materials such as a medium substrate, ceramics, a metal plate belt line, a metal body and the like; 2) Can be a planar structure or a three-dimensional structure; 3) Can be a single-layer structure or a multi-layer structure; 4) The cell shape may be square, rectangular, triangular or polygonal; 5) Multiple series or parallel resonant circuits can be constructed to obtain one or more transmission zeros or reflection zeros, thereby expanding the stop band and passband bandwidth; 6) Only a parallel resonant circuit can be constructed to obtain an optimal reflection zero; 7) Can support dual polarization, single polarization and circular polarization electromagnetic wave
The FSS designed by the invention can realize the reflection of more than 35% of relative bandwidth in the L frequency band, the reflection coefficient is more than-0.2 dB, and meanwhile, the transmission of more than 45% of relative bandwidth in the H frequency band, and the transmission coefficient is more than-0.3 dB. The minimum frequency ratio of the L frequency band to the H frequency band can reach 1.5:1, up to 5:1. in the joint simulation of the L-band passive antenna and the H-band active antenna, the L-band passive antenna gain is only reduced by 0.2dB, and the average gain of the H-band active antenna is not reduced.
The FSS provided by the invention is suitable for active passive fusion base stations and antenna products with various specifications and models, and can be particularly used for the following scenes: 1. the sites cannot be newly added; 2. limited wind load and other factors can not increase 5G sky sites; 3. affected by the early 4G sky, the 5G active sky hangs high and low or sight-line shielding sites exist.
The invention provides FSS, and a low-frequency series LC circuit and a high-frequency parallel LC circuit are constructed in a metal strip, so that a transmission zero point and a reflection zero point are respectively obtained, and the low-resistance high-pass filtering effect of the space electromagnetic wave is realized; meanwhile, based on the FSS design method, various FSS unit embodiments are provided. The optimal embodiment adopts a double-layer structure, has extremely low transmission/reflection loss and good space dispersion characteristic, and can effectively inhibit secondary radiation of induced current in a wave-transmitting frequency band and ensure the radiation characteristic of a sky interface. The frequency selective surface has the functions of reflecting low-frequency electromagnetic waves and transmitting high-frequency electromagnetic waves, can realize common caliber of the multi-frequency antenna, simultaneously inhibit different-frequency coupling, and ensure independent deployment, separation and maintenance of the multi-frequency antenna.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention should be included in the protection scope of the present invention.
Claims (12)
1. A frequency selective surface unit comprising:
a first surface formed of a plurality of first metal strips interlaced with each other;
the second surface is formed by a plurality of second metal strips, wherein each second metal strip is provided with a second inter-strip gap, and the metal strips on two sides of the second inter-strip gap are connected through metal strip wires so as to form a parallel resonance LC circuit in an H frequency band;
the first surface and the second surface are fixed on the same side or front and back surfaces of the supporting plate.
2. The frequency selective surface unit according to claim 1, wherein first inter-band gaps are distributed at both ends of each of the first metal strips, and the second inter-band gaps are located in a predetermined area above or below the first inter-band gaps with the first and second surfaces fixed to the front and back surfaces of the support plate to constitute a series resonant LC circuit in an L-band.
3. The frequency selective surface unit of claim 1, wherein the first metal strip comprises: the metal strip comprises a first central metal strip and two first side metal strips, wherein the first central metal strip is positioned in the middle of the first metal strip, the two first side metal strips are respectively distributed at two ends of the first metal strip, and a first inter-strip gap is formed between each first side metal strip and the first central metal strip.
4. The frequency selective surface unit of claim 1, wherein the second metal strip comprises:
and the two second side end metal strips are distributed on two sides of the second inter-belt gap and are connected through the metal belt wires.
5. The frequency selective surface unit according to claim 2, wherein the second inter-band gap is located in a predetermined area above or below the first inter-band gap to constitute a series resonant LC circuit in the L-band, comprising:
the first center metal strip, the two first side metal strips, the two second side metal strips and the metal strip line are connected in series to form a series resonance LC circuit in the L frequency band.
6. The frequency selective surface unit according to claim 1, wherein the first metal strip and/or the second metal strip is at least one of:
an elongated metal strap wire;
bending the metal strap wire;
a metal coil;
and (5) a metal via.
7. The frequency selective surface unit according to claim 1, wherein the first metal strip and the second metal strip are connected in one of the following ways:
the coplanar coupling lines are connected;
non-coplanar coupling line connections;
the interlaced wires are connected.
8. The frequency selective surface unit of claim 1, wherein the support plate is one of:
a dielectric substrate;
a ceramic;
a sheet metal strip line;
a metal body.
9. A frequency selective surface, characterized by being constituted by a frequency selective surface element period extension according to any of claims 1-8.
10. The frequency selective surface of claim 9, wherein the frequency selective surface comprises one of:
-said frequency selective surface element of single layer period extension;
said frequency selective surface element of a dual layer period extension;
the frequency selective surface unit of multi-layer period extension.
11. A spatial filtering method implemented using the frequency selective surface of claim 10, comprising:
and adjusting the L value or the C value of the series resonant LC circuit and the parallel resonant LC circuit to control the transmission frequency band and the reflection frequency band of the frequency selective surface unit.
12. The method as recited in claim 11, further comprising:
the number of the series resonant LC circuits and the parallel resonant LC circuits are adjusted to control the transmission bandwidth and the reflection bandwidth of the frequency selective surface unit.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211021650.5A CN117673762A (en) | 2022-08-24 | 2022-08-24 | Frequency selective surface and spatial filtering method |
| PCT/CN2023/108731 WO2024041280A1 (en) | 2022-08-24 | 2023-07-21 | Frequency selective surface and spatial filtering method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211021650.5A CN117673762A (en) | 2022-08-24 | 2022-08-24 | Frequency selective surface and spatial filtering method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117673762A true CN117673762A (en) | 2024-03-08 |
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ID=90012386
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211021650.5A Pending CN117673762A (en) | 2022-08-24 | 2022-08-24 | Frequency selective surface and spatial filtering method |
Country Status (2)
| Country | Link |
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| CN (1) | CN117673762A (en) |
| WO (1) | WO2024041280A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030142036A1 (en) * | 2001-02-08 | 2003-07-31 | Wilhelm Michael John | Multiband or broadband frequency selective surface |
| US7071889B2 (en) * | 2001-08-06 | 2006-07-04 | Actiontec Electronics, Inc. | Low frequency enhanced frequency selective surface technology and applications |
| CN103490175B (en) * | 2013-09-23 | 2016-01-06 | 摩比天线技术（深圳）有限公司 | A kind of integrated base station antenna |
| CN110416735A (en) * | 2018-07-16 | 2019-11-05 | 西安电子科技大学 | Flexible multi-layered frequency-selective surfaces with transmission zero |
| CN111786122A (en) * | 2020-07-26 | 2020-10-16 | 中国人民解放军国防科技大学 | Reconfigurable wave-absorbing and wave-transmitting integrated FSS with high transmittance |
| CN215680980U (en) * | 2021-09-29 | 2022-01-28 | 京信通信技术(广州)有限公司 | Passive antenna and multi-frequency fusion base station antenna |
-
2022
- 2022-08-24 CN CN202211021650.5A patent/CN117673762A/en active Pending
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2023
- 2023-07-21 WO PCT/CN2023/108731 patent/WO2024041280A1/en unknown
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| WO2024041280A1 (en) | 2024-02-29 |
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