CN112701489B - Bandpass Frequency Selective Surface Structure Based on Antenna-Filter-Antenna - Google Patents

Abstract

The invention provides a band-pass frequency selection surface structure based on an antenna, a filter and an antenna, which comprises a frequency selection unit, wherein the frequency selection unit is formed by sequentially laminating a first radiation patch, a first dielectric plate, a first metal floor, a second dielectric plate, a resonance layer, a third dielectric plate, a second metal floor, a fourth dielectric plate and a second radiation patch; the projections of first gaps arranged on the first metal floor fall on the first radiation patches; projections of second gaps arranged on the second metal floor fall on the second radiation patches; the resonance layer is composed of a first microstrip and a second microstrip which are mutually orthogonal, and the projection of the first gap falling on the resonance layer and the projection of the second gap falling on the resonance layer are separated at two sides of the first microstrip; the length direction of the first slot and the length direction of the second slot are consistent with the length direction of the first microstrip. The structure generates four transmission poles and two transmission zeros, and has stable quasi-elliptic filtering response, high selectivity, good angle stability and low section.

Description

Bandpass Frequency Selective Surface Structure Based on Antenna-Filter-Antenna

technical field

The present invention relates to the technical field of frequency surface selection, in particular to a bandpass frequency selective surface structure based on an antenna-filter-antenna.

Background technique

Frequency Selective Surface (FSS) is a two-dimensional periodic surface structure that can reflect or transmit electromagnetic waves. There are two types of traditional frequency selective surfaces, which are the slot type and the frequency selective surface composed of patch periodic elements. The patch type has the same metal element periodically on the dielectric surface. The other is the gap type, which is a structure in which gaps are periodically etched on the metal plate. When the FSS is in a resonance state, the incident electromagnetic wave is totally reflected or totally transmitted, which can be used as a spatial filter and can be widely used in anti-electromagnetic interference, electromagnetic compatibility, anti-electric radiation, antenna decoupling and so on. At present, the method of improving the selectivity of the frequency selective surface generally adopts a multi-layer structure or a 3D structure, which will result in a thick section of the overall structure, and a complex assembly is required after the 3D structure is processed.

According to investigation and understanding, the existing technologies that have been disclosed are as follows:

1) The invention patent application with the Chinese patent application number 201710415782.9 discloses an ultra-wide passband frequency selective surface structure, which aims to improve the angular stability of the frequency selective surface. The structure consists of five layers, which include: a first radiation patch layer, a first intermediate dielectric plate, a second radiation patch layer, a second intermediate dielectric plate, and a third radiation patch layer. The five layers are pressed together in sequence. The structural unit of the first metal layer and the third metal layer is a rectangle with the same length and width, and the center of the unit is a rectangular patch smaller than the unit size with the same length and width. The four corners of the unit are connected. After the periodic extension of the plane, a square patch array with cross-shaped patches interleaved is presented; the second radiating patch layer, the unit of which is a rectangle of the same size as the above, with a cross-shaped metal line in the center, at the midpoint of the unit Rectangular radiating patches are connected with cross-shaped metal wires at all positions, and after plane extension, a grid array with square patches at the midpoint between the intersections is presented. The frequency selection surface has ultra-wide passband characteristics, and can be freely combined with most of the thickness of the skin, shell, protective cover and other structures, and has high use value. The disadvantage, however, is that the frequency selective surface structure is less selective to frequencies outside the passband.

2) The invention patent application with the Chinese patent application number 201810577469.X discloses that the invention discloses a high-angle stable frequency selective surface and a design method thereof, which includes M*N periodically arranged frequency selective surface units, frequency selective The surface unit includes a dielectric plate and a metal ring pair composed of two oppositely arranged open metal rings on the upper and lower surfaces of the dielectric plate, and the opening directions of the two metal rings on the surface are opposite to each other, and the first rectangular slits of the two radiation patches are opposite to each other, and They are all 180° rotationally symmetrical about the normal line of the dielectric plate. The positions of the metal ring pair and the radiation patch pair on the same surface are correspondingly located at the position where the projection of the metal ring pair on the upper surface on the lower surface is rotated by 90°. The metal vias connect the two pairs of metal The open end of the ring corresponds to the upper and lower links, and the stroke is a selective surface unit structure. It can be used in many scenarios that have strict requirements on the angular stability of frequency selective surfaces, such as reflector antennas. The disadvantage, however, is that the frequency selective surface structure is less selective to frequencies outside the passband.

3) The invention patent application with the Chinese patent application number 201910331692.0 discloses a band-pass 3D frequency selective surface, which aims to improve the angular stability of the wide-bandpass 3D frequency surface, including m*n resonance units: each resonance unit includes five Layer dielectric board and four metal layers, the metal layer includes four stepped ring structures on the upper surface of the upper dielectric board and the lower surface of the lower dielectric board, and the upper and lower surfaces of the middle dielectric board surround the four edges of the dielectric board. The square metal ring structure formed by the edge, And two groups of 2*2 square ring structures inside the square metal ring, the centers of the first group of square ring structures are at the four diagonal positions of the dielectric plate, and the centers of the second group of rings are connected to the adjacent centers of the first group of rings At the midpoint of , the stepped annular structures on the upper surface of the upper dielectric plate and the lower surface of the lower dielectric plate are connected correspondingly through wires. The structure improves the angular stability while realizing the edge steep drop passband, so that it can be used in the case of a large incident angle, and can be used in communication and radar. But the disadvantages are: the angular stability of the frequency selective surface structure is general, and the overall structure profile is thick.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to design a band-pass frequency selective surface structure that is easy to process, has a low profile, good angular stability and high selectivity, and solves the defects of the prior art such as poor out-of-band selectivity and thicker structural profile. .

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

The band-pass frequency selective surface structure based on antenna-filter-antenna includes a frequency selective unit, the frequency selective unit is composed of a first radiation patch, a first dielectric plate, a first metal floor, a second dielectric plate, a resonance layer, a third dielectric plate, a second metal floor, a fourth dielectric plate and a second radiation patch; the first metal floor is provided with a first slot, and the projection of the first slot falls on the on the first radiation patch; the second metal floor is provided with a second slot, and the projections of the second slot all fall on the second radiation patch; the resonance layer is composed of mutually orthogonal first A microstrip and a second microstrip are formed, the projection of the first slot falling on the resonance layer and the projection of the second slot falling on the resonance layer are separated on both sides of the first microstrip; the first The length direction of the slit and the length direction of the second slit are consistent with the length direction of the first microstrip.

Further, the length directions of the first slit and the second slit are both parallel to the length direction of the first microstrip.

Further, both the first radiation patch and the second radiation patch are rectangular patches, and the projection of the first radiation patch falling on the resonance layer is the same as the projection of the second radiation patch falling on the resonance layer. The projections of the resonant layer are on both sides of the first microstrip.

Further, the first radiation patch and the second radiation patch are both square metal patches used to form a TM ₀₁ mold or a TM ₁₀ mold, and the projection of the center of the first slit is the same as the first radiation patch. The centers of the patches are coincident, and the projection of the center of the second slit is coincident with the center of the second radiation patch.

Further, the distance from the projection of the first slot on the resonant layer to the first microstrip is equal to the distance from the projection of the second slot on the resonant layer to the first microstrip, Both are 0.1-0.5 central operating frequency wavelengths.

Further, the lengths of the first slot and the second slot are equal, and both are 0.1-0.4 wavelengths of the central working frequency; the widths of the first slot and the second slot are 0.01-0.03 the central working frequency wavelength; the size of the first radiation patch and the second radiation patch are the same, and the side length is 0.2-0.5 wavelengths of the central operating frequency.

Further, the projection of the center of the first slot on the resonance layer and the projection of the center of the second slot on the resonance layer are both located on the second microstrip; the first microstrip The two ends of the microstrip are also provided with a first branch node and a second branch node, and the total length of the first microstrip, the first branch node and the second branch node is 0.2-0.5 central operating frequency wavelength; so The length of the second microstrip is 0.2-0.5 wavelengths of the central operating frequency.

Further, the center of the first microstrip coincides with the center of the second microstrip.

Further, the first branch and the second branch are mirror-symmetrical with respect to the second microstrip.

Further, the frequency selection units are provided with M*N, which are respectively tiled on the same plane and the spacing between two adjacent frequency selection units is 0.4-0.8 wavelengths of the central working frequency; the first medium The thickness of the plate is 1/60-1/20 wavelengths of the central working frequency, and the dielectric constant is 2.0-4.0; the thickness of the second dielectric plate is 1/60-1/20 wavelengths of the central working frequency, and the dielectric constant is 2.0-4.0; the thickness of the third dielectric plate is 1/60-1/20 wavelengths of the central operating frequency, and the dielectric constant is 2.0-4.0; the thickness of the fourth dielectric plate is 1/60-1/ 20 wavelengths at the center operating frequency, the dielectric constant is 2.0-4.0; the first dielectric plate, the second dielectric plate, the third dielectric plate and the fourth dielectric plate are all rectangular, and the four The projections of the center on the resonance layer are all coincident with the center of the second microstrip; wherein, M and N are natural numbers, and M≥5, N≥5.

The beneficial effect of the present invention is that: the first radiation patch and the first slot are combined to form a receiving antenna/transmitting antenna, the second radiation patch and the second slot are combined to form a transmitting antenna/receiving antenna, and The first metal floor including the first slot, the resonant layer, and the second metal floor including the second slot are combined to form a high-order filter, thereby realizing a high-order frequency selective surface. The first radiation patch and the second radiation patch generate two transmission poles through resonance; even mode resonance and odd mode resonance are generated when the mutually orthogonal first microstrip and second microstrip resonate, and then form two transmission poles. The first microstrip also generates a low-frequency stop-band transmission zero, and signals in two directions higher than the resonant frequency cancel each other to form a high-frequency stop-band transmission zero. To sum up, the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present application generates a total of four transmission poles and two transmission zeros, and has a good and stable quasi-elliptical filter response and high selectivity, and the angle Good stability. Since it is formed by superimposing multi-layered layered structures, the structure is simple, the profile is low, and it is easy to process.

Description of drawings

The specific structure of the present invention will be described in detail below in conjunction with the accompanying drawings

1 is a schematic cross-sectional view of a second microstrip through a bandpass frequency selective surface structure based on an antenna-filter-antenna of the present invention;

2 is a schematic diagram 1 of a partial layered structure of the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

3 is a schematic diagram 2 of a partial layered structure of the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

4 is a schematic diagram 3 of a partial layered structure of the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

5 is a schematic diagram 4 of a partial layered structure of the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

6 is a schematic diagram 5 of a partial layered structure of the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

Fig. 7 is the electromagnetic simulation curve diagram of the S-parameter performance of the band-pass frequency selective surface structure based on the antenna-filter-antenna of the present invention;

8 is a simulation curve of the reflection coefficient under different incident wave angles based on the bandpass frequency selective surface structure of the antenna-filter-antenna of the present invention;

9 is a transmission coefficient simulation curve under different incident wave angles based on the bandpass frequency selective surface structure of the antenna-filter-antenna of the present invention;

Among them, 1-first radiation patch, 2-first dielectric board, 3-first metal floor, 31-first slot, 4-second dielectric board, 5-resonant layer, 51-first microstrip, 52 -Second microstrip, 53-First stub, 54-Second stub, 6-Third dielectric plate, 7-Second metal floor, 71-Second slot, 8-Fourth dielectric plate, 9-Second Radiation patch.

Detailed ways

According to the specific embodiments of the technical content, structural features, achieved objectives and effects of the present invention, detailed descriptions are given in conjunction with the accompanying drawings, and the details are as follows:

Example 1

Please refer to FIG. 1 to FIG. 6 , an antenna-filter-antenna-based bandpass frequency selective surface structure, including a frequency selective unit, the frequency selective unit is composed of a first radiation patch 1 and a first dielectric plate stacked in sequence 2. The first metal floor 3, the second dielectric plate 4, the resonance layer 5, the third dielectric plate 6, the second metal floor 7, the fourth dielectric plate 8 and the second radiation patch 9 are formed; the first metal floor 3 is provided with a first slit 31, and the projection of the first slit 31 falls on the first radiation patch 1, that is, the projection of the first slit 31 falls on the plane where the first radiation patch 1 is located All fall on the first radiation patch 1; the second metal floor 7 is provided with a second slit 71, and the projections of the second slit 71 all fall on the second radiation patch 9, namely The projections of the second slot 71 on the plane where the second radiation patch 9 is located all fall on the second radiation patch 9; the resonance layer 5 is composed of the first microstrip 51 and the second The microstrip 52 is formed, the projection of the first slot 31 falling on the resonance layer 5 and the projection of the second slot 71 falling on the resonance layer 5 are separated from the two sides of the first microstrip 51; The length direction of a slit 31 and the length direction of the second slit 71 are consistent with the length direction of the first microstrip 51 .

The first radiation patch 1 and the first slot 31 are combined to form a receiving antenna/transmitting antenna, the second radiation patch 9 and the second slot 71 are combined to form a transmitting antenna/receiving antenna, and the first The first metal floor 3 of the slot 31 , the resonant layer 5 and the second metal floor 7 containing the second slot 71 are combined to form a high-order filter, thereby realizing a high-order frequency selective surface. The first radiation patch 1 and the second radiation patch 9 generate two transmission poles through resonance; when the mutually orthogonal first microstrip 51 and the second microstrip 52 resonate, even mode resonance and odd mode resonance are generated , and then form two transmission poles. The first microstrip 51 also generates a low-frequency stop-band transmission zero, and signals in two directions higher than the resonant frequency cancel each other to form a high-frequency stop-band transmission zero—both transmission zeros can improve transmission characteristics. To sum up, the bandpass frequency selective surface structure based on the antenna-filter-antenna of the present application generates a total of four transmission poles and two transmission zeros, and has a good and stable quasi-elliptical filter response and high selectivity, and the angle is stable. Sex is good. It is formed by the superposition of multi-layer layered structures, with simple structure, low profile and easy processing.

Example 2

On the basis of the above structure, the length directions of the first slit 31 and the second slit 71 are both parallel to the length direction of the first microstrip 51 . Under the irradiation of plane waves whose polarization direction is perpendicular to the first slot 31/second slot 71, when the incident angle increases from 0° to 40°, it still has a very stable frequency response and good angular stability.

Example 3

On the basis of the above structure, the first radiation patch 1 and the second radiation patch 9 are both rectangular patches, and the projection of the first radiation patch 1 on the resonance layer 5 is the same as the The projection of the second radiating patch 9 falling on the resonant layer 5 is located on both sides of the first microstrip 51, further improving the stability of the quasi-elliptical filter response based on the bandpass frequency selective surface structure of the antenna-filter-antenna , selectivity and angular stability.

Example 4

On the basis of the above structure, the first radiation patch 1 and the second radiation patch 9 are both square metal patches used to form a TM ₀₁ die or a TM ₁₀ die. The projection on the plane where the first radiation patch 1 is located coincides with the center of the first radiation patch 1, and the projection on the plane where the second radiation patch 9 is located at the center of the second slit 71 is the same as the projection on the plane where the second radiation patch 9 is located. The centers of the second radiation patches 9 are coincident, which further improves the stability, selectivity and angular stability of the quasi-elliptical filter response based on the antenna-filter-antenna bandpass frequency selective surface structure. The first radiation patch 1 and the second radiation patch 9 generate two transmission poles through resonance, forming a TM ₀₁₀ mode in three-dimensional space.

Example 5

On the basis of the above structure, the distance between the projection of the first slot 31 falling on the resonance layer 5 to the first microstrip 51 and the projection of the second slot 71 falling on the resonance layer 5 to the first microstrip 51 The distances of the first microstrips 51 are equal, which are 0.1-0.5 wavelengths of the central operating frequency. The stability, selectivity and angular stability of the quasi-elliptical filter response based on the bandpass frequency selective surface structure of the antenna-filter-antenna are further improved.

Example 6

On the basis of the above structure, the lengths of the first slot 31 and the second slot 71 are equal, and both are 0.1-0.4 wavelengths of the central operating frequency; the widths of the first slot 31 and the second slot 71 are 0.01-0.03 wavelengths of the central working frequency; the size of the first radiation patch 1 and the second radiation patch 9 are the same, and the side length is 0.2-0.5 wavelengths of the central working frequency wavelength. The stability, selectivity and angular stability of the quasi-elliptical filter response based on the bandpass frequency selective surface structure of the antenna-filter-antenna are further improved.

Example 7

On the basis of the above structure, the projection of the center of the first slot 31 falling on the resonance layer 5 and the projection of the center of the second slot 71 falling on the resonance layer 5 are both located on the second microstrip 52 The two ends of the first microstrip 51 are also provided with a first branch 53 and a second branch 54, the first microstrip 51, the first branch 53 and the second branch 54 three The total length is 0.2-0.5 wavelengths of the central working frequency; the length of the second microstrip 52 is 0.2-0.5 wavelengths of the central working frequency. The stability, selectivity and angular stability of the quasi-elliptical filter response based on the bandpass frequency selective surface structure of the antenna-filter-antenna are further improved.

Example 8

On the basis of the above structure, the center of the first microstrip 51 coincides with the center of the second microstrip 52, which further improves the stability of the quasi-elliptical filter response based on the antenna-filter-antenna bandpass frequency selective surface structure Sex, selectivity, and angular stability.

Example 9

On the basis of the above structure, the first branch 53 and the second branch 54 are mirror-symmetrical with respect to the second microstrip 52, which further improves the accuracy of the bandpass frequency selective surface structure based on the antenna-filter-antenna. Stability, selectivity, and angular stability of elliptic filter responses.

Example 10

On the basis of the above structure, there are M*N of the frequency selection units, which are respectively tiled on the same plane and the spacing between two adjacent frequency selection units is 0.4-0.8 wavelengths of the central working frequency; the The thickness of the first dielectric plate 2 is 1/60-1/20 wavelength of the central working frequency, and the dielectric constant is 2.0-4.0; the thickness of the second dielectric plate 4 is 1/60-1/20 central working frequency wavelength, the dielectric constant is 2.0-4.0; the thickness of the third dielectric plate 6 is 1/60-1/20 wavelengths of the central operating frequency, and the dielectric constant is 2.0-4.0; the thickness of the fourth dielectric plate 8 is 1/60-1/20 wavelengths of the central operating frequency, and the dielectric constant is 2.0-4.0; the first dielectric plate 2, the second dielectric plate 4, the third dielectric plate 6 and the fourth dielectric plate The dielectric plates 8 are all rectangular, and the projections of the four centers on the resonant layer 5 coincide with the center of the second microstrip 52; wherein, M and N are natural numbers, and M≥5, N≥5 . The stability, selectivity and angular stability of the quasi-elliptical filter response based on the bandpass frequency selective surface structure of the antenna-filter-antenna are further improved.

In order to further discuss the beneficial effects of the present invention, further description is made in conjunction with the following test examples:

Test example

A bandpass frequency selective surface structure based on antenna-filter-antenna, comprising a frequency selective unit, the frequency selective unit is composed of a first radiation patch 1, a first dielectric plate 2, a first metal floor 3, The second dielectric plate 4 , the resonance layer 5 , the third dielectric plate 6 , the second metal floor 7 , the fourth dielectric plate 8 and the second radiation patch 9 are constituted.

The first metal floor 3 is provided with a first slit 31, and the projections of the first slit 31 all fall on the first radiation patch 1; the second metal floor 7 is provided with a second slit 71 , the projections of the second slot 71 all fall on the second radiation patch 9; the resonant layer 5 is composed of a first microstrip 31 and a second microstrip 71 that are orthogonal to each other, the first slot The projection of 31 falling on the resonance layer 5 and the projection of the second slit 71 falling on the resonance layer 5 are separated from the two sides of the first microstrip 51; the first slit 31 and the second slit 71 The length direction of each is parallel to the length direction of the first microstrip 51 .

The first radiation patch 1 and the second radiation patch 9 are both square metal patches used to form a TM ₀₁ mode or a TM ₁₀ mode, and the first radiation patch 1 falls on the resonance layer The projection of 5 and the projection of the second radiation patch 9 falling on the resonant layer 5 are on both sides of the first microstrip 51 . The projection of the center of the first slit 31 coincides with the center of the first radiation patch 1 , and the projection of the center of the second slit 71 coincides with the center of the second radiation patch 9 .

The distance between the projection of the first slot 31 falling on the resonance layer 5 to the first microstrip 51 and the projection of the second slot 71 falling on the resonance layer 5 to the first microstrip 51 are The distances are equal, both 4.2mm.

The lengths of the first slot 31 and the second slot 71 are the same, and both are 4.2 mm; the first radiation patch 1 and the second radiation patch 9 have the same size, and the side length is 9.5 mm.

Further, the projection of the center of the first slot 31 falling on the resonance layer 5 and the projection of the center of the second slot 71 falling on the resonance layer 5 are both located on the second microstrip 52; Both ends of the first microstrip 51 are also provided with a first branch 53 and a second branch 54, and the total length of the first microstrip 51, the first branch 53 and the second branch 54 is is 14.6mm; the length of the second microstrip 52 is 10.9mm. The center of the first microstrip 51 coincides with the center of the second microstrip 52 . The first branch 53 and the second branch 54 are mirror-symmetrical with respect to the second microstrip 52 .

Further, there are 20*20 frequency selection units, which are respectively tiled on the same plane. Along the direction perpendicular to the second microstrip 52, the distance between two adjacent frequency selection units is 15mm; along the length direction of the second microstrip 52, the distance between two adjacent frequency selection units is 20mm. The first dielectric board 2, the second dielectric board 4, the third dielectric board 6 and the fourth dielectric board 8 are all Rogers 4003C, and the dielectric constants are all 3.38; the first dielectric board 2 , the second dielectric plate 4, the third dielectric plate 6 and the fourth dielectric plate 8 are all rectangular, and the projections of the centers of the four on the resonant layer 5 are the same as the second microstrip The centers of 52 coincide. The thickness of the first dielectric board 2 and the fourth dielectric board 8 is 1.524 mm, and the thickness of the second dielectric board 4 and the third dielectric board 6 is 0.813 mm.

For the above structure, the electromagnetic simulation software CST is used to obtain the simulation results. For details, see the S-parameter performance electromagnetic simulation curve in Figure 7, the reflection system number electromagnetic simulation curve in Figure 8, and the transmission coefficient simulation curve in Figure 9.

It can be seen from Fig. 7 that the structure of the present invention has a quasi-elliptical frequency response. In Fig. 7 |S11| is the return loss of the input port, and |S21| is the forward transmission coefficient of the input port. It can be seen that the value of |S11| is lower than -10dB; the center frequency of the 3dB passband of the frequency selective surface is 7.07GHz, and two transmission zeros are generated at 6.71GHz and 7.59GHz, which improves the low-frequency stopband and high-frequency stopband The roll-off characteristic improves the frequency selection performance.

It can be seen from FIG. 8 and FIG. 9 that when the incident angle increases from 0° to 40°, the present invention still has a very stable frequency response and good angular stability, which increases its practical application value.

To sum up, the bandpass frequency selective surface structure based on the antenna-filter-antenna provided by the present invention generates four transmission poles and two transmission zeros in total, and has good and stable quasi-elliptical filter response and high selectivity, And the angle stability is good. Since it is formed by superimposing multi-layered layered structures, the structure is simple, the profile is low, and it is easy to process.

Here the first, the second... only represent the distinction of their names, not the difference in their importance and position.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (9)

1. A band-pass frequency selective surface structure based on an antenna-filter-antenna, characterized in that it includes a frequency selection unit, and the frequency selection unit consists of a first radiation patch, a first dielectric plate, and a first metal floor layered in sequence , a second dielectric plate, a resonance layer, a third dielectric plate, a second metal floor, a fourth dielectric plate and a second radiation patch; The first metal floor is provided with a first slit, and the projection of the first slit falls on the first radiation patch; the second metal floor is provided with a second slit, and the second slit The projections of all fall on the second radiation patch; The resonance layer is composed of a first microstrip and a second microstrip that are orthogonal to each other, and the projection of the first slot on the resonance layer is separated from the projection of the second slot on the resonance layer. Both sides of the first microstrip; the length direction of the first slit and the length direction of the second slit are parallel to the length direction of the first microstrip; Both the first radiation patch and the second radiation patch are square metal patches used to form a TM ₀₁ die or a TM ₁₀ die. 2. The bandpass frequency selective surface structure based on antenna-filter-antenna according to claim 1, wherein the first radiating patch and the second radiating patch are both rectangular patches, and The projection of the first radiation patch on the resonance layer and the projection of the second radiation patch on the resonance layer are located on both sides of the first microstrip. 3. The bandpass frequency selective surface structure based on antenna-filter-antenna according to claim 2, wherein the projection of the center of the first slot coincides with the center of the first radiating patch, and the The projection of the center of the second slot coincides with the center of the second radiation patch. 4. The bandpass frequency selective surface structure based on antenna-filter-antenna as claimed in claim 3, wherein the first slot falls on the distance of the projection of the resonance layer to the first microstrip The distance from the projection of the second slot falling on the resonance layer to the first microstrip is equal to 0.1-0.5 wavelengths of the central working frequency. 5. The bandpass frequency selective surface structure based on antenna-filter-antenna according to claim 4, wherein the lengths of the first slot and the second slot are equal, and both are 0.1-0.4 centers Working frequency wavelength; the width of the first slot and the second slot is 0.01-0.03 wavelengths of the central working frequency; the size of the first radiation patch and the second radiation patch are the same, and the side length is 0.2 -0.5 wavelength of center operating frequency. 6. The bandpass frequency selective surface structure based on antenna-filter-antenna according to claim 5, wherein the center of the first slot falls on the projection of the resonance layer and the center of the second slot The projections falling on the resonance layer are all located on the second microstrip; both ends of the first microstrip are also provided with a first branch and a second branch, the first microstrip, the second branch The total length of the first branch and the second branch is 0.2-0.5 wavelengths of the central working frequency; the length of the second microstrip is 0.2-0.5 wavelengths of the central working frequency. 7. The antenna-filter-antenna based bandpass frequency selective surface structure of claim 6, wherein the center of the first microstrip coincides with the center of the second microstrip. 8. The bandpass frequency selective surface structure based on antenna-filter-antenna according to claim 7, wherein the first branch and the second branch are mirror-symmetrical with respect to the second microstrip . 9. The antenna-filter-antenna-based bandpass frequency selective surface structure according to any one of claims 1 to 8, wherein the frequency selective units are provided with M*N, which are respectively tiled on the same plane The spacing between two adjacent frequency selection units is 0.4-0.8 wavelengths of the central working frequency; the thickness of the first dielectric plate is 1/60-1/20 wavelengths of the central working frequency, and the dielectric constant is 2.0-4.0; the thickness of the second dielectric plate is 1/60-1/20 wavelengths of the central operating frequency, and the dielectric constant is 2.0-4.0; the thickness of the third dielectric plate is 1/60-1/20 the center operating frequency wavelengths, the dielectric constant is 2.0-4.0; the thickness of the fourth dielectric plate is 1/60-1/20 center operating frequency wavelengths, the dielectric constant is 2.0-4.0; the first dielectric plate , the second dielectric plate, the third dielectric plate and the fourth dielectric plate are all rectangular, and the projections of the centers of the four on the resonance layer coincide with the center of the second microstrip; Among them, M and N are natural numbers, and M≥5, N≥5.

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