Dual-polarization angle selective surface structure with wide passband angle and out-of-band steep drop

Abstract

The invention discloses a dual-polarization angle selective surface structure with a wide passband angle and out-of-band steep drop, which is formed by mutually connecting a plurality of periodic units, each periodic unit is provided with at least two metal structure layers from top to bottom, and an air dielectric layer unit is arranged between the adjacent metal structure layers; wherein the metal structure layer comprises a dielectric substrate, an upper surface metal layer and a lower surface metal layer are arranged on the upper surface and the lower surface of the dielectric substrate respectively, and the upper surface metal layer and the lower surface metal layer are connected through a metal via hole formed in the dielectric substrate; the upper surface metal layer and the lower surface metal layer have the same structure, and each periodic unit internally comprises Jerusalem-type metal sheets which are circumferentially distributed around the center of the dielectric substrate; the Jerusalem type metal sheet support arms are mutually connected; the middle through hole of the cross-shaped metal main arm of the Jerusalem metal sheet is the end part of the metal via hole, and the metal via hole is connected with the middle part of the cross-shaped metal main arm at the corresponding position of the upper and lower surfaces of the dielectric substrate.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wave filtering, in particular to a dual-polarization angle selection surface with wide passband angle and out-of-band steep drop characteristics. Background Art

[0002] In the past few decades, controlling the propagation of electromagnetic waves has been a hot topic for scientists, including the selection of the frequency, polarization and incident angle of electromagnetic waves. The theory and structural design related to the frequency filtering and polarization selection of electromagnetic waves have made great progress. In contrast, the analysis and design of the selection of the incident angle of electromagnetic waves has developed relatively slowly.

[0003] Angle-selective surface structures are generally array structures that are periodically arranged along one or two dimensions, allowing electromagnetic waves incident at a certain angle to pass through and reflecting electromagnetic waves at other incident angles. This characteristic makes it widely used in the microwave field, such as antenna sidelobe suppression, angle-selective absorbers, high-efficiency energy capture, anti-interference communications, transmitter angle control, etc.; At present, the design method of angle-selective surface structures is mainly based on the extraction of equivalent impedance or equivalent dielectric parameters. This method requires the extraction of equivalent impedance or dielectric parameters based on the calculation of the reflection transmission coefficient of the angle-selective surface structure, and finally further design based on the equivalent impedance or dielectric parameters. Since it is impossible to directly determine the correspondence between the geometric structure and the equivalent impedance or dielectric parameters for any periodic structure, the design method based on the extraction of equivalent impedance or equivalent dielectric parameters is relatively cumbersome.

[0004] In practical applications, it is often necessary to simultaneously control dual-polarized electromagnetic waves, but most of the current angle-selective surface structures can only control the incidence of single-polarized electromagnetic waves, and there are relatively few studies on the simultaneous control of dual-polarized electromagnetic waves. The use of angle-selective surface structures with wide passband angles in antennas can reduce the loss of effective antenna radiation and increase the integration and portability of communication systems. However, the passband angle of the angle-selective structure that can currently control dual-polarized electromagnetic waves is relatively narrow, reaching a maximum of 25°. The use of angle-selective surface structures with steep out-of-band drop in antennas can effectively suppress antenna sidelobes and improve the antenna's directivity and anti-interference capabilities. Therefore, how to efficiently design angle-selective surface structures with wide passband angles, high selectivity, and polarization insensitivity is an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a dual-polarization angle selection surface structure with a wide passband angle and a steep drop out of the band, which can solve the problems of narrow passband angle and poor steep drop out of the band to a certain extent.

[0006] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0007] A dual-polarization angle-selective surface structure with a wide passband angle and a steep drop out of the band, which is composed of a plurality of periodic units connected to each other, each periodic unit is provided with at least two metal structure layers from top to bottom, and an air dielectric layer unit is provided between adjacent metal structure layers;

[0008] The metal structure layer includes a dielectric substrate, and an upper surface metal layer and a lower surface metal layer are respectively arranged on the upper and lower surfaces of the dielectric substrate, and the upper surface metal layer and the lower surface metal layer are connected through metal vias opened in the dielectric substrate; the upper surface metal layer and the lower surface metal layer have the same structure, and each periodic unit includes a Jerusalem-type metal sheet distributed circumferentially around the center of the dielectric substrate, and the Jerusalem-type metal sheet is a cross-shaped structure, including a cross metal main arm and four branches respectively located vertically at the ends of the cross metal main arm; the branches of the Jerusalem-type metal sheet of each periodic unit are connected to each other; the middle through hole of the cross metal main arm is the end of the metal via, and the metal via connects the middle of the cross metal main arm at the corresponding position on the upper and lower surfaces of the dielectric substrate.

[0009] Furthermore, the arm of the Jerusalem-type metal sheet forms an angle of 45° with the edge of the dielectric substrate of the periodic unit.

[0010] Furthermore, the metal structure layer is provided with two layers, the first metal structure layer and the second metal structure layer are equivalent to microwave network A and microwave network B, and the reflection coefficient of the first metal structure layer is characterized as the scattering parameter of microwave network A. The phase is expressed as The reflection coefficient of the second metal structure layer is characterized by the scattering parameter of microwave network B The phase is expressed as

[0011] At the transmission angle θ0, the reflection coefficient amplitudes of the first metal structure layer and the second metal structure layer satisfy: The thickness of the air dielectric layer between the first metal structure layer and the second metal structure layer satisfies Where k is the wave number of the operating frequency; at the reflection angle θ r At the location, the reflection coefficients of the first metal structure layer and the second metal structure layer satisfy

[0012] Furthermore, the specific method for determining the thickness h2 of the air medium layer is as follows:

[0013] Firstly, the structural parameters of the metal structural layer in the angle selective surface structure are determined;

[0014] Secondly, electromagnetic simulation software is used to simulate and calculate the angle-selective surface structure with determined structural parameters. During the calculation, the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80° is simulated and calculated, and the wave transmission angle range is determined based on the reflection coefficient value in the simulation calculation result. The formula is used to calculate the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80°. Calculating a series of air dielectric layer thicknesses h2 corresponding to each wave transmission angle in the wave transmission angle range at different values ​​of the parameter m under a preset polarization mode; wherein the preset polarization mode is TE polarization or TM polarization;

[0015] Finally, after obtaining h2 corresponding to each wave transmission angle determined in two different polarization modes, h2 that satisfies the transmission coefficients of the electromagnetic wave incident angles in two different polarization modes is selected as the final determined air dielectric layer thickness; wherein the range of the electromagnetic wave incident angle is the wave transmission angle range.

[0016] Furthermore, the metal structure layer is provided with four layers, the structures of the four metal structure layers are the same, and the structures of the first and second metal structure layers and the first air dielectric layer and the third air dielectric layer between the third and fourth metal structure layers are the same.

[0017] Furthermore, the first metal structure layer to the second metal structure layer are combined to form a combined structure C, which is equivalent to a microwave network C. The reflection coefficient of the combined structure C can be characterized as a scattering parameter of the microwave network C. The phase is expressed as The third metal structure layer to the fourth metal structure layer are combined to form a combined structure D, which is equivalent to a microwave network D. The reflection coefficient of the combined structure D is characterized as a scattering parameter of the microwave network D. The phase is expressed as At the transmission angle θ0, the reflection coefficient amplitudes of the combined structures C and D satisfy: The thickness of the air dielectric layer between the two should meet m=0,±1,±2,…; at reflection angle θ r At this point, the reflection coefficients of the combined structures C and D satisfy

[0018] Furthermore, the dielectric substrate adopts a square plate with a relative dielectric constant of 2.08, the side length of the periodic unit P=16mm, and the thickness of the dielectric substrate h1=1.6mm; the length of each main arm of the cross metal main arm in the Jerusalem-type metal sheet is L1=10mm, and the main arm width is W1=2mm; the branch arm length is L2=8mm, and the branch arm width is W2=3mm; the metal via radius r1=1mm.

[0019] Furthermore, the thickness of the first air medium layer and the third air medium layer is h2=23 mm.

[0020] Furthermore, the thickness of the second air medium layer is h3=23 mm.

[0021] Compared with the prior art, the present invention has the following technical features:

[0022] 1. In the solution of the present invention, only the reflection coefficient parameters of the metal structure layer need to be calculated, and there is no need to extract equivalent impedance or equivalent parameters, so the design process is simple.

[0023] 2. The scheme of the present invention can achieve efficient transmission of TE and TM polarized electromagnetic waves with wide passband angle, and the passband angle reaches 40°.

[0024] 3. The angle selection structural surface described in the present invention has good out-of-band steepness. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the angle selection surface structure provided by the present invention when two metal structure layers are provided;

[0026] Figure 2 A top view of a Jerusalem-type metal sheet having an angle-selective surface structure provided by the present invention;

[0027] Figure 3 A three-dimensional view of a metal structural layer of an angle-selective surface structure provided by the present invention;

[0028] Figure 4 A schematic diagram of the angle selection surface structure provided by the present invention when four metal structure layers are provided;

[0029] Figure 5 A side view of the overall structure of the angle selection surface structure provided by the present invention;

[0030] Figure 6 A schematic diagram of a microwave network of the angle-selective surface structure provided by the present invention when there are two metal structure layers;

[0031] Figure 7 A schematic diagram of a microwave network of a combination structure C and a combination structure D of the angle selective surface structure provided by the present invention;

[0032] Figure 8 is the reflection coefficient phase of the metal structure layer described in Example 1 when the electromagnetic wave is incident at 0° to 40°;

[0033] Fig. 9is the reflection coefficient amplitude of the metal structure layer described in Example 1 when the electromagnetic wave is incident at 0° to 80°, wherein (a) is the reflection coefficient amplitude of the metal structure layer when TE polarization is incident; (b) is the reflection coefficient amplitude of the metal structure layer 1 when TM polarization is incident;

[0034] Fig.10 The wave transmission coefficient of the angle selective surface structure described in Example 1 at the working frequency band of 9.35 GHz for TE and TM polarizations;

[0035] Fig.11 is the reflection coefficient phase of the combined structure C described in Example 2 when the electromagnetic wave is incident at 0° to 40°;

[0036] Fig.12 is the reflection coefficient amplitude of the combination structure C described in Example 2 when the electromagnetic wave is incident at 0° to 80°, wherein (a) is the reflection coefficient amplitude of the combination structure C when TE polarization is incident; (b) is the reflection coefficient amplitude of the combination structure C when TM polarization is incident;

[0037] Fig.13 It is the wave transmission coefficient of TE and TM polarization of the angle selective surface structure described in Example 2 at the working frequency band of 9.35 GHz, wherein (a) is the wave transmission coefficient of the angle selective surface structure when TE polarization is incident; (b) is the wave transmission coefficient of the angle selective surface structure when TM polarization is incident.

[0038] Explanation of the numbers in the figure: 1 metal structure layer, 2 air dielectric layer, 11 dielectric substrate, 12 metal via, 13 Jerusalem type metal sheet, 131 cross metal main arm, 132 support arm. DETAILED DESCRIPTION

[0039] The present invention provides a dual-polarization angle-selective surface structure with a wide passband angle and a steep out-of-band drop. The structure only needs to adjust the reflection coefficient of the metal structure layer to satisfy the relationship of equal amplitude and the thickness of the air dielectric layer to satisfy the relationship of the phase and of the reflection coefficient to obtain an angle-selective surface at a specified angle. The structure can achieve a wide passband angle and good out-of-band cutoff characteristics when TE and TM polarized electromagnetic waves are incident.

[0040] See attached Figure 1 and 2 The angle selective surface structure provided by the present invention is composed of a plurality of periodic units connected to each other, each periodic unit is provided with at least two metal structure layers from top to bottom, and an air dielectric layer is provided between adjacent metal structure layers;

[0041] The metal structure layer includes a dielectric substrate, and an upper surface metal layer and a lower surface metal layer are respectively arranged on the upper and lower surfaces of the dielectric substrate, and the upper surface metal layer and the lower surface metal layer are connected through metal vias opened in the dielectric substrate; the structure of the upper surface metal layer and the lower surface metal layer are exactly the same, and each periodic unit includes Jerusalem-type metal sheets distributed circumferentially around the center of the dielectric substrate, see Figure 2 The Jerusalem-type metal sheet is a cross-shaped structure, including a cross metal main arm and four arms vertically located at the ends of the cross metal main arm; the arms of the Jerusalem-type metal sheet form a 45° angle with the edge of the dielectric substrate of the periodic unit, and the arms of the Jerusalem-type metal sheet of each periodic unit are connected to each other. The middle through hole of the cross metal main arm is the end of the metal via, and the metal via connects the middle of the cross metal main arm at the corresponding position of the upper and lower surfaces of the dielectric substrate.

[0042] Solution 1:

[0043] See also Figure 1 , which is a schematic diagram of the structure when the present invention adopts two metal structural layers.

[0044] The first metal structure layer and the second metal structure layer can be represented by microwave network A and microwave network B respectively. The reflection coefficient of the first metal structure layer can be represented as the scattering parameter of microwave network A. The phase is expressed as The reflection coefficient of the second metal structure layer can be characterized as the scattering parameter of microwave network B The phase is expressed as The thickness of the air dielectric layer between the first metal structure layer and the second metal structure layer is h2; at the wave transmission angle θ0, the reflection coefficient amplitude of the first metal structure layer and the second metal structure layer satisfies: The thickness of the air dielectric layer between the two should meet Where k is the wave number of the operating frequency; at the reflection angle θ r At the location, the reflection coefficients of the first metal structure layer and the second metal structure layer satisfy In order to ensure that the amplitudes of the reflection coefficients of microwave network A and microwave network B are always equal, a method is adopted herein in which the structures of the first metal structure layer and the second metal structure layer are completely identical.

[0045] In this embodiment, the specific method for determining the thickness h2 of the air dielectric layer is as follows:

[0046] First, the structural parameters of the metal structure layer in the angle-selective surface structure are determined, including the dielectric constant, shape, side length, and thickness of the dielectric substrate; the length and width of the cross metal main arm in the Jerusalem-type metal sheet; the length and width of the branch arm; and the radius of the metal via.

[0047] Secondly, electromagnetic simulation software is used to simulate and calculate the angle-selective surface structure with determined structural parameters. During the calculation, the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80° is simulated and calculated, and the wave transmission angle range is determined based on the reflection coefficient value in the simulation calculation result. The formula is used to calculate the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80°. Calculating a series of air dielectric layer thicknesses h2 corresponding to each wave transmission angle in the wave transmission angle range at different values ​​of the parameter m under a preset polarization mode; wherein the preset polarization mode is TE polarization or TM polarization;

[0048] Finally, after obtaining h2 corresponding to each wave transmission angle determined in two different polarization modes, h2 that satisfies the transmission coefficients of the electromagnetic wave incident angles in two different polarization modes is selected as the final determined air dielectric layer thickness; wherein the range of the electromagnetic wave incident angle is the wave transmission angle range.

[0049] Option 2:

[0050] In another embodiment of the present invention, a four-layer metal structure is provided. Figure 5 As shown; wherein, the structures of the four metal structure layers are the same, and the structures of the first and second metal structure layers and the first air dielectric layer and the third air dielectric layer between the third and fourth metal structure layers are the same.

[0051] like Figure 7 As shown, the first metal structure layer to the second metal structure layer are combined to form a combined structure C, which can be characterized as a microwave network C, and the reflection coefficient of the combined structure C can be characterized as a scattering parameter of the microwave network C. The phase is expressed as The third metal structure layer to the fourth metal structure layer are combined to form a combined structure D. The combined structure D can be regarded as a microwave network D. The reflection coefficient of the combined structure D can be characterized as a scattering parameter of the microwave network D. The phase is expressed as At the transmission angle θ0, the reflection coefficient amplitudes of the combined structures C and D satisfy: The thickness of the air dielectric layer between the two should meet At the reflection angle θ r At this point, the reflection coefficients of the combined structures C and D satisfy In order to ensure that the reflection coefficient amplitudes of microwave network C and microwave network D are always equal, a method in which the structures of combined structure C and combined structure D are exactly the same is adopted here, that is, the structures of the metal structure layers in this scheme are the same, and the structure (thickness) of the air dielectric layer between the first and second metal structure layers and the air dielectric layer between the third and fourth metal structure layers are the same.

[0052] In this scheme, the method for determining the thickness h3 of the second air dielectric layer between the combined structure C and the combined structure D is similar to that of scheme one, that is, the combined structure C and the combined structure D are respectively regarded as the first metal structure layer and the second metal structure layer of scheme one for calculation.

[0053] Embodiment 1:

[0054] refer to Figures 1 to 3 In this embodiment, a structure with two metal structural layers is given. The design of the metal structural layer and the air dielectric layer therebetween is described in the previous text and will not be repeated here. The microwave network diagram of this structure can be referred to Figure 6 , where the first metal structure layer is represented by microwave network A, the second metal structure layer is represented by microwave network B, and the air dielectric layer is represented by a transmission line with a length of h2; since the first metal structure layer is exactly the same as the second metal structure layer, the reflection coefficients of the two microwave networks satisfy the condition of equal amplitude.

[0055] In this embodiment, the dielectric substrate of the metal structure layer is a square plate with a relative dielectric constant of 2.08, the period (side length) of the periodic unit is P = 16 mm, and the thickness of the dielectric substrate is h1 = 1.6 mm; see Figure 3 In the Jerusalem type metal sheet, each main arm length L1 = 10 mm, main arm width W1 = 2 mm; branch arm length L2 = 8 mm, branch arm width W2 = 3 mm; metal via radius r1 = 1 mm.

[0056] Based on the finite element commercial electromagnetic simulation software ANSYS HFSS2023R1, the reflection coefficient phase of the first metal structure layer in Example 1 under TE polarization mode and TM polarization mode at 0° incidence is simulated and calculated. The calculation results can be referred to Figure 8 ; The reflection coefficient amplitude of the first metal structure layer is simulated and calculated when the TE polarization or TM polarization electromagnetic wave is incident at 0°~80°. The calculation results can be referred to Fig. 9 At 9.35 GHz, the reflection coefficient of the metal structure layer 1 for electromagnetic waves incident at 0° to 40° is not 1, but close to 0, and 0° to 40° is defined as the wave transmission angle θ0; the reflection coefficient of electromagnetic waves incident at 60° to 80° is close to 1, and 60° to 80° can be defined as the reflection angle θr ;like Figure 8 As shown, at 9.35GHz, θ0=0° electromagnetic wave is incident, the thickness h2 of the air dielectric layer 1 should be greater than 0 and satisfy The solution is h2=6.8, 22.8, 38.8 mm…; for electromagnetic waves with other transmission angles and polarizations, the corresponding h2 can be calculated by the same method; finally, considering that the transmission coefficients of the incident angles of 0° to 40° in the two polarization modes should be satisfied, the thickness of the air dielectric layer between the first metal structure layer and the second metal structure layer is selected to be h2=23 mm (rounding is adopted in this embodiment.)

[0057] Based on the finite element commercial electromagnetic simulation software ANSYS HFSS2023R1, the wave transmission coefficient of the angle-selective surface structure in Example 1 when TE polarization and TM polarization electromagnetic waves are incident at 0° to 80° at 9.35GHz is simulated and calculated. The results are as follows: Fig.10 Reference Fig.10 , the horizontal axis represents the incident angle θ of the incident wave, and the vertical axis represents the amplitude of the wave transmission coefficient; the results show that in the working frequency band of 9.35GHz, the 1dB passband angle when TE polarized electromagnetic waves are incident is 0°~40°; the transition angle range of the wave transmission coefficient from -1dB to -15dB is 40°~50°, and the out-of-band steepness is good; the 1dB passband angle when TM polarization is 0°~37°; the transition angle range of the wave transmission coefficient from -1dB to -15dB is 37°~59°. This structure has the dual-polarization angle selection characteristics of wide passband angle and out-of-band steepness.

[0058] Embodiment 2:

[0059] refer to Figure 4 and Figure 5 In this embodiment, four metal structure layers are used. The first metal structure layer, the second metal structure layer and the first air dielectric layer are combined to form a combined structure C, and the third metal structure layer, the fourth metal structure layer and the third air dielectric layer are combined to form a combined structure D. The microwave network schematic diagram of this structure can be referred to Figure 7 ; The second air dielectric layer is characterized by a transmission line of length h3; Since the combination structure C is exactly the same as the combination structure D, the reflection coefficients of the two microwave networks satisfy the condition of equal amplitude

[0060] In this embodiment, the dielectric substrate is a square plate with a relative dielectric constant of 2.08, the period (side length) of the periodic unit is P = 16 mm, and the thickness of the dielectric substrate is h1 = 1.6 mm; see Figure 3The length of each main arm of the cross metal main arm in the Jerusalem type metal sheet is L1 = 10mm, and the width of the main arm is W1 = 2mm; the length of the branch arm is L2 = 8mm, and the width of the branch arm is W2 = 3mm; the radius of the metal via is r1 = 1mm, and the thickness of the first air dielectric layer and the third air dielectric layer is h2 = 23mm.

[0061] Based on the finite element commercial electromagnetic simulation software ANSYS HFSS2023R1, the reflection coefficient phase of the combined structure C in the above embodiment is simulated and calculated when the TE polarization and TM polarization electromagnetic waves are incident at 0°. The calculation results can be referred to Fig.11 ; The reflection coefficient amplitude of the composite structure C under TE polarization and TM polarization electromagnetic waves incident at 0°~80° is simulated and calculated. The calculation results can be referred to Fig.12 At 9.35 GHz, the reflection coefficient of the metal structure layer 1 for electromagnetic waves incident at 0° to 40° is not 1, but is close to 0, and 0° to 40° is defined as the wave transmission angle θ0. The reflection coefficient of electromagnetic waves incident at 60° to 80° is close to 1, and 60° to 80° can be defined as the reflection angle θ r ;like Fig.11 As shown, at 9.35GHz, θ0=0° electromagnetic wave is incident, the thickness h3 of the air dielectric layer 2 should be greater than 0, and the thickness h3 of the second air dielectric layer should satisfy The solution is h3=9.07, 25.07, 41.07mm…; for other transmission angles and polarization conditions, the corresponding h3 can be calculated by the same method; finally, considering comprehensively that the transmission coefficients of the incident angles of 0°~40° in the two polarization modes should be satisfied, h3=23mm is selected.

[0062] Based on the finite element commercial electromagnetic simulation software ANSYS HFSS2023R1, the transmission coefficient of the angle-selective surface structure in the above embodiment 2 under TE polarization and TM polarization electromagnetic waves at 0° to 80° incidence at 9.35GHz was simulated and calculated. The results are as follows: Fig.13 As shown; Reference Fig.13 , the horizontal axis represents the incident angle θ of the electromagnetic wave, and the vertical axis represents the amplitude of the transmission coefficient; the results show that in the working frequency band of 9.35GHz, the 1dB passband angles of TE and TM polarized electromagnetic waves are both 0°~40°; the transition angle range of the wave transmission coefficient from -1dB to -15dB when TE polarized incident is 40°~50°; the transition angle range of the wave transmission coefficient from -1dB to -15dB when TM polarized incident is 40°~52°. This structure has the characteristics of wide passband angle, steep drop-off characteristics outside the band, and polarization insensitivity.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A dual-polarization angle-selective surface structure with a wide passband angle and a steep out-of-band drop, characterized in that: The angle selective surface structure is composed of a plurality of periodic units connected to each other, each periodic unit is provided with at least two metal structure layers from top to bottom, and an air medium layer unit is provided between adjacent metal structure layers; The metal structure layer includes a dielectric substrate, and an upper surface metal layer and a lower surface metal layer are respectively arranged on the upper and lower surfaces of the dielectric substrate, and the upper surface metal layer and the lower surface metal layer are connected through metal vias opened in the dielectric substrate; the upper surface metal layer has the same structure as the lower surface metal layer, and each periodic unit includes a plurality of Jerusalem-type metal sheets distributed circumferentially around the center of the dielectric substrate, and the Jerusalem-type metal sheet is a cross-shaped structure, including a cross metal main arm and four branches respectively located vertically at the ends of the cross metal main arm; the innermost branches of each Jerusalem-type metal sheet are connected to each other; the middle through hole of the cross metal main arm is the end of the metal via, and the metal via connects the middle of the cross metal main arm at the corresponding position on the upper and lower surfaces of the dielectric substrate.

2. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 1, characterized in that: The arm of the Jerusalem-type metal sheet forms an angle of 45° with the edge of the dielectric substrate of the periodic unit.

3. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 1, characterized in that: The metal structure layer is provided with two layers, the first metal structure layer and the second metal structure layer are equivalent to microwave network A and microwave network B, and the reflection coefficient of the first metal structure layer is characterized as the scattering parameter of microwave network A. The phase is expressed as The reflection coefficient of the second metal structure layer is characterized by the scattering parameter of microwave network B The phase is expressed as At the transmission angle θ0, the reflection coefficient amplitudes of the first metal structure layer and the second metal structure layer satisfy: The thickness of the air dielectric layer between the first metal structure layer and the second metal structure layer satisfies Where k is the wave number of the operating frequency; at the reflection angle θ r At the location, the reflection coefficients of the first metal structure layer and the second metal structure layer satisfy 4. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 3, characterized in that: The specific method for determining the thickness h2 of the air dielectric layer is as follows: Firstly, the structural parameters of the metal structural layer in the angle selective surface structure are determined; Secondly, electromagnetic simulation software is used to simulate and calculate the angle-selective surface structure with determined structural parameters. During the calculation, the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80° is simulated and calculated, and the wave transmission angle range is determined based on the reflection coefficient value in the simulation calculation result. The formula is used to calculate the reflection coefficient amplitude of the first metal structure layer under the preset polarization mode when the electromagnetic wave is incident at 0° to 80°. Calculating a series of air dielectric layer thicknesses h2 corresponding to each wave transmission angle in the wave transmission angle range at different values ​​of the parameter m under a preset polarization mode; wherein the preset polarization mode is TE polarization or TM polarization; Finally, after obtaining h2 corresponding to each wave transmission angle determined in two different polarization modes, h2 that satisfies the transmission coefficients of the electromagnetic wave incident angles in two different polarization modes is selected as the final determined air dielectric layer thickness; wherein the range of the electromagnetic wave incident angle is the wave transmission angle range.

5. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 1 or 3, characterized in that: The metal structure layer is provided with four layers, and the structures of the four metal structure layers are the same, and the structures of the first and second metal structure layers and the first and third air medium layers between the third and fourth metal structure layers are the same.

6. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 5, characterized in that: The first metal structure layer to the second metal structure layer are combined to form a combined structure C, which is equivalent to a microwave network C. The reflection coefficient of the combined structure C can be characterized as a scattering parameter of the microwave network C. The phase is expressed as The third metal structure layer to the fourth metal structure layer are combined to form a combined structure D, which is equivalent to a microwave network D. The reflection coefficient of the combined structure D is characterized as a scattering parameter of the microwave network D. The phase is expressed as At the transmission angle θ0, the reflection coefficient amplitudes of the combined structures C and D satisfy: The thickness of the air dielectric layer between the two should meet At the reflection angle θ r At this point, the reflection coefficients of the combined structures C and D satisfy 7. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 5, characterized in that: The dielectric substrate is a square plate with a relative dielectric constant of 2.08, the side length P of the periodic unit is 16 mm, and the thickness h1 of the dielectric substrate is 1.6 mm; each main arm length L1 of the cross metal main arm in the Jerusalem type metal sheet is 10 mm, and the main arm width W1 is 2 mm; The arm length L2=8mm, the arm width W2=3mm; the metal via radius r1=1mm.

8. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 5, characterized in that: The thickness of the first air medium layer and the third air medium layer is h2=23 mm.

9. The dual-polarization angle selective surface structure with wide passband angle and steep out-of-band drop according to claim 5, characterized in that: The thickness of the second air dielectric layer h3=23 mm.

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