A broadband angle selective surface based on double-layer coupling

Abstract

This invention provides a broadband angle-selective surface based on dual-layer coupling, composed of multiple angle-selective surface units with identical structures arranged periodically. Each angle-selective surface unit includes an upper angle-selective layer, an intermediate air layer, and a lower angle-selective layer arranged sequentially. The upper and lower angle-selective layers are identical in size and shape, and their projections correspond. Each includes an upper metal layer, an intermediate dielectric substrate, and a lower metal layer arranged sequentially. The upper and lower metal layers are also identical in size and shape, and their projections correspond; both are metal layers with a Jerusalem cross-shaped aperture structure at their center. Under different angles of oblique incidence of dual-polarized electromagnetic waves, the metal surface is excited to produce different resonances, achieving transmission effects for perpendicular and small-angle oblique incidence of electromagnetic waves, as well as band-stop effects for large-angle oblique incidence. Ultimately, this invention enables angle selection of electromagnetic waves incident at different angles and possesses broadband transmission and high selectivity characteristics.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and further relates to a frequency selective surface with angle selectability in the field of electromagnetic field and microwave technology, which can be used to resist co-channel interference and suppress antenna sidelobes. Background Technology

[0002] Angle-selective surfaces (AMS) are an advanced technology that selectively transmits electromagnetic waves based on their frequency and angle of incidence, showing great potential in suppressing antenna sidelobes and co-channel interference. Current AMS utilizes multi-layer coupling of frequency-selective surfaces to achieve angle selectivity, allowing single-layer structures to exhibit certain angle selectivity for electromagnetic waves incident at different angles; double-layer structures are beneficial for broadening the transmission bandwidth under different incident angles and enhancing the band-stop effect under large-angle oblique incidence. However, current AMS still suffers from significant differences in transmission performance under different polarizations, a narrow overall transmission bandwidth under perpendicular and small-angle oblique incidence, and low selectivity, indicating room for further performance improvement. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention proposes a broadband angle-selective surface based on dual-layer coupling, which aims to broaden the transmission bandwidth of dual-polarized electromagnetic waves under vertical and small-angle oblique incidence, enhance the band-stop effect of dual-polarized electromagnetic waves under large-angle oblique incidence, and improve selectivity.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A broadband angle selection surface based on dual-layer coupling is composed of multiple angle selection surface units with the same structure arranged periodically. The angle selection surface unit includes an upper angle selection layer, an intermediate air layer and a lower angle selection layer arranged sequentially.

[0006] The upper and lower corner selection layers have the same size and shape, and their projections correspond. Each layer includes an upper metal layer, an intermediate dielectric plate, and a lower metal layer arranged sequentially.

[0007] The upper and lower metal layers are identical in size and shape, and their projections correspond; both are metal layers with a Jerusalem cross-shaped perforation structure in the center.

[0008] In one embodiment, the upper corner selection layer, the middle air layer, and the lower corner selection layer are arranged in sequence, and the center of each of them is located on the central axis of the unit.

[0009] In one embodiment, both the upper and lower corner selective layers are sequential cascaded structures formed by an upper metal layer, an intermediate dielectric substrate, and a lower metal layer, thereby achieving selective transmission characteristics for electromagnetic waves with different incident angles.

[0010] In one embodiment, the Jerusalem cross-shaped aperture structure has each arm having a vertically bent structure, and each arm is rotationally symmetrical about the center of the metal layer it is located in.

[0011] In one embodiment, the Jerusalem cross-shaped aperture structure has a vertical bend structure in each arm.

[0012] In one embodiment, the vertical bending structure is located at the center of each arm.

[0013] In one embodiment, the vertical bending structure has a bent portion that is a square groove, and the width of the square groove opening is greater than the width of the remaining openings in each arm.

[0014] In one embodiment, the cross-section of the angle-selecting surface unit is square, and the Jerusalem cross-shaped perforation structure has a long groove vertically connected to the end of each arm, with the long side of the long groove parallel to the edge of the unit, and the remaining part of each arm has the same perforation width as the long groove.

[0015] In one embodiment, the cross-sectional side length of the angle-selective surface unit is 10mm, the thickness of the intermediate air layer is 11mm, the length of the pores parallel to the edge of the Jerusalem cross pore structure is 3.9mm, and the width is 0.5mm; the width of the frame-shaped pores above the Jerusalem cross pore structure is 0.8mm, the width of the remaining pores is 0.5mm, and the overall length of the Jerusalem cross pore structure is 9mm.

[0016] In one embodiment, the broadband angle-selective surface exhibits dual-polarized wave transmission performance under electromagnetic wave incidence of 0° to 20°, |S 21 |<-1dB; produces band-stop performance under an incidence angle greater than 50° and maintains |S under an incidence angle of 80°. 21 |<-20dB.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] First, the overall structure of this invention mainly consists of three cascaded layers: an upper corner selective layer, an intermediate air layer, and a lower corner selective layer. The upper corner selective layer itself is composed of three cascaded layers: an upper metal layer, a dielectric substrate, and a lower metal layer. Both the upper and lower corner selective layers are designed with two metal layers. This double-metal-layer and double-corner selective layer structure helps to broaden the transmission bandwidth and enhances band-stop performance under large-angle oblique incidence of electromagnetic waves. This allows the transmission bandwidth of this invention to be broadened in the angular domain under both vertical and small-angle oblique incidence at a fixed frequency band, and to exhibit band-stop performance under large-angle oblique incidence of electromagnetic waves. This invention utilizes the double-layer coupling effect to broaden the transmission bandwidth.

[0019] Secondly, the metal layer design employs a method of creating voids within the metal layer, with the voids forming a bent Jerusalem structure. The center of each void is the unit center, and the bending method involves setting up a square-shaped bend on the Jerusalem crossarm. The entire void structure is rotationally symmetrical around the unit center. The four metal layers within the unit are designed in the same way, with the upper and lower corner layers cascading as a metal layer-intermediate dielectric plate-metal layer. The unit structure is cascaded as an upper corner layer-intermediate air layer-lower corner layer, offering the advantages of simple structure and easy fabrication.

[0020] Third, in this invention, when TE waves and TM waves are incident perpendicularly to a 20° oblique incidence, |S 21 |>-1dB; When the electromagnetic wave is incident at an angle greater than 20°, the transmission performance gradually decreases. When the incident angle is greater than 80°, the transmission performance of TE and TM waves increases significantly. 21 |<-20dB, exhibiting high selectivity for dual-polarized wave transmission states. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the angle-selective surface unit structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the upper corner selection layer of the present invention.

[0023] Figure 3 This is a schematic diagram of the lower corner selection layer of the present invention.

[0024] Figure 4 This is a top view of the angle-selective surface unit structure of the present invention;

[0025] Figure 5 This is a schematic diagram of the frequency domain S-parameter characteristics in a simulation experiment according to an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the S-parameter characteristics of the angular domain in a simulation experiment according to an embodiment of the present invention. Detailed Implementation

[0027] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0028] Reference Figure 1 The present invention is based on a broadband angle selection surface with dual-layer coupling, which is mainly composed of multiple angle selection surface units with the same structure arranged periodically. The angle selection surface unit includes an upper angle selection layer 1, an intermediate air layer 2, and a lower angle selection layer 3 arranged sequentially. The upper angle selection layer 1, the intermediate air layer 2, and the lower angle selection layer 3 are arranged from top to bottom, and the center of each of them is located on the central axis of the unit.

[0029] The upper corner layer 1 and the lower corner layer 3 are the same size and shape, and their projections correspond. The upper corner layer 1, the middle air layer 2, and the lower corner layer 3 are arranged in sequence. The overall unit structure is composed of the three cascaded together, and the center of each of the three is the same, which is the unit center.

[0030] Reference Figure 2 The upper corner selection layer 1 includes an upper metal layer 11, a dielectric substrate 12, and a lower metal layer 13; see reference. Figure 3 The lower corner layer 3 includes an upper metal layer 31, a dielectric substrate 32, and a lower metal layer 33. The upper metal layer 11 and the lower metal layer 13 are identical in size and shape, and their projections correspond; both are metal layers with a Jerusalem cross-shaped perforation structure at the center. Correspondingly, the upper metal layer 31 and the lower metal layer 33 are identical in size and shape, and their projections correspond; both are metal layers with a Jerusalem cross-shaped perforation structure at the center.

[0031] In the upper corner selective layer 1, the cascaded structure of the upper metal layer 11, the dielectric substrate 12, and the lower metal layer 13 achieves selective transmission characteristics for electromagnetic waves with different incident angles. Correspondingly, in the lower corner selective layer 3, the cascaded structure of the upper metal layer 31, the dielectric substrate 32, and the lower metal layer 33 achieves selective transmission characteristics for electromagnetic waves with different incident angles.

[0032] This invention designs an upper metal layer 11 and a lower metal layer 13 in the upper corner selection layer 1, and simultaneously designs an upper metal layer 31 and a lower metal layer 33 in the lower corner selection layer 3. This allows the overall structure of the unit to enhance the wave transmission performance under small-angle electromagnetic wave incidence, and at the same time enhance the band-stop effect under large-angle oblique electromagnetic wave incidence, thereby achieving angle selection of the transmitted wave.

[0033] Meanwhile, the cascaded design of the upper metal layer 11, dielectric substrate 12, and lower metal layer 13 in the upper corner selection layer 1, as well as the cascaded design of the upper corner selection layer 1, intermediate air layer 2, and lower corner selection layer 3, enables coupling between the two-layer patches, widening the passband bandwidth in the corner domain and generating a band-stop effect under large-angle oblique incidence of electromagnetic waves. Furthermore, the cascaded dual-layer metal design is beneficial for widening the corner domain transmission bandwidth.

[0034] Reference Figure 2 In this invention, the Jerusalem cross-shaped perforation structure on the upper metal layer 11 has four Jerusalem perforations 111, and the Jerusalem cross-shaped perforation structure on the lower metal layer 13 has four Jerusalem perforations 131. The two Jerusalem cross-shaped perforation structures have the same shape and corresponding dimensions, with the center of the perforation coinciding with the center of the unit. They are printed on the upper and lower sides of the dielectric substrate 12, respectively, forming a cascaded structure of the upper metal layer 11, the dielectric substrate 12, and the lower metal layer 13.

[0035] Correspondingly, refer to Figure 3The Jerusalem cross-shaped perforation structure on the upper metal layer 31 has four Jerusalem perforations 311, and the Jerusalem cross-shaped perforation structure on the lower metal layer 33 has four Jerusalem perforations 331. The two Jerusalem cross-shaped perforation structures have the same shape and corresponding dimensions, with the center of the perforation coinciding with the center of the unit. They are printed on the upper and lower sides of the dielectric substrate 32, respectively, forming a cascaded structure of the upper metal layer 31, the dielectric substrate 32, and the lower metal layer 33.

[0036] Furthermore, in the upper metal layer 11, a Jerusalem perforation 111 serves as one arm of the Jerusalem cross perforation structure, and it may have a vertically bent structure. The four bent Jerusalem perforations 111 are rotationally symmetrical around the center of the upper metal layer 11, forming a Jerusalem cross perforation structure with vertical bending. Except for the perforations, the rest of the upper metal layer 11 is entirely printed with metal.

[0037] Preferably, there is only one vertical bending structure on each bent Jerusalem aperture 111 of the present invention, and it is preferably arranged in the center of the arm. The bent portion of the vertical bending structure is a square groove, and the width of the square groove aperture is greater than the width of the apertures in the remaining part of the arm.

[0038] Furthermore, the overall direction of the Jerusalem aperture 111 of the present invention is parallel to the edge of the unit. Specifically, for the angular selection surface unit with a square cross-section, the end of the Jerusalem aperture 111 is vertically connected to a long groove, the long side of the long groove is parallel to the edge of the unit, and except for the square groove aperture, the width of the remaining apertures is consistent with the width of the long groove aperture.

[0039] The bent structure is used to reduce the length of the parallel structure and the equivalent capacitance, so that the transmission point of the ASS is at 10 GHz.

[0040] The square slot width is greater than the long slot aperture width to appropriately reduce the metal area, cut off the current along the bend, and at the same time weaken the equivalent capacitance of the bend and strengthen the odd-mode resonance.

[0041] The structure of the upper metal layer 31, the lower metal layer 33, and the lower metal layer 13 of the present invention is the same as that of the upper metal plate 11.

[0042] In a further embodiment of the present invention, in the upper corner selection layer 1, the dielectric substrate 12 is a Rogers RT-duroid 5880 dielectric substrate with a relative permittivity of 2.2, a loss tangent of 0.0009, and a thickness of 1.575 mm. The dielectric substrate 12 provides an electrical insulating layer between the upper metal layer 11 and the lower metal layer 13, providing support for the metal patch structure.

[0043] In a further embodiment of the present invention, in the lower corner selection layer 3, the second dielectric substrate 32 is a Rogers RT-duroid5880 dielectric substrate with a relative permittivity of 2.2, a loss tangent of 0.0009, and a thickness of 1.575 mm. The second dielectric substrate 32 provides an electrical insulating layer between the upper metal layer 31 and the lower metal layer 33, providing support for the metal patch structure.

[0044] Reference Figure 1 and Figure 4 The design unit size is p = 10 mm, the dielectric plate thickness is t = 10 mm, and the air layer thickness is h = 11 mm; the length of the long slot is l1 = 3.9 mm, and the width is w1 = 0.5 mm; the width of the groove in the upper frame of the Jerusalem perforated cross structure is w2 = 0.8 mm, the width of the remaining part of the cross structure arm is w3 = 0.5 mm, and the overall length of the Jerusalem structure is l2 = 9 mm; the center of the entire structure coincides with the center of the unit and is rotationally symmetrical about the center of the unit.

[0045] The working principle of this invention is:

[0046] The angle-selective surface unit of this invention is mainly composed of a cascaded upper angle-selective layer 1, an intermediate air layer 2, and a lower angle-selective layer 3 from top to bottom. The proposed angle-selective structure's single-layer surface exhibits angle selectivity for TE and TM waves under both perpendicular and small-angle oblique incidence, as well as for band-stop characteristics under oblique incidence. In this invention, the unit structure utilizes Jerusalem-style pores added to the metal layer to excite odd-mode resonances under large-angle oblique incidence of electromagnetic waves, inducing band-stop characteristics, while under perpendicular incidence, odd-mode resonances are not excited, and the structure exhibits band-pass characteristics. By cascading two identical angle-selective layers, the passband bandwidth in the angular domain can be widened and the band-stop characteristics enhanced without affecting wave transmission under perpendicular and small-angle incidence conditions. The intermediate air layer 2 cascaded between the upper and lower angle-selective layers results in different matching conditions under different electromagnetic wave incidence angles, enhancing the band-stop effect without affecting the transmission effect of electromagnetic waves under perpendicular and small-angle oblique incidence.

[0047] The technical effects of the present invention will be further explained below with reference to simulation experiments:

[0048] The S-parameter curves obtained by modeling and simulating the embodiments of the present invention using the commercial simulation software CST Studio Suite 2024 are shown below. Figure 5 As shown. Figure 5 The horizontal axis represents the angle value in degrees, and the vertical axis represents the S-parameter in dB. Figure 5 The black dashed lines and gray dotted lines in the image represent the transmission coefficients |S of the TE and TM waves. 21 |Curve.

[0049] Reference Figure 5When electromagnetic waves are incident perpendicularly, the transmission point of TE and TM waves is 10 GHz.

[0050] Reference Figure 6 Within the angular domain, when TE and TM waves are incident perpendicularly to a 20° oblique incidence, the angle-selective surface exhibits good wave transmission performance. 21 |>-1dB; When electromagnetic waves are incident at an angle greater than 20°, the transmission performance gradually decreases. For TE and TM waves with an incident angle greater than 50°, |S 21 |<-10dB, when the incident angle is greater than 80°, TE wave and TM wave|S 21 |<-20dB, exhibiting band-stop characteristics.

[0051] Although specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A broadband angle-selective surface based on dual-layer coupling, comprising a periodic arrangement of multiple angle-selective surface units with identical structures, characterized in that, The angle selection surface unit includes an upper angle selection layer (1), an intermediate air layer (2), and a lower angle selection layer (3) arranged sequentially. The upper corner selection layer (1) and the lower corner selection layer (3) have the same size and shape, and their projections correspond. They are both sequential cascaded structures formed by the upper metal layer, the middle dielectric plate and the lower metal layer, which realize the selective transmission characteristics of electromagnetic waves with different incident angles. The upper and lower metal layers are identical in size and shape, and their projections correspond. Both are metal layers with a Jerusalem cross-shaped perforation structure in the center. Each arm of the Jerusalem cross-shaped perforation structure has a vertical bending structure, and each arm is rotationally symmetrical about the center of its respective metal layer. The bending part of the vertical bending structure is a square groove, and the width of the square groove is greater than the width of the remaining holes in each arm.

2. The broadband angle-selective surface based on dual-layer coupling according to claim 1, characterized in that, The upper corner selection layer (1), the middle air layer (2) and the lower corner selection layer (3) are arranged in sequence, and the center of each of them is located on the central axis of the unit.

3. The broadband angle-selective surface based on dual-layer coupling according to claim 1, characterized in that, The Jerusalem cross-shaped aperture structure has a vertical bend in each arm.

4. The broadband angle-selective surface based on dual-layer coupling according to claim 3, characterized in that, The vertical bending structure is located at the center of each arm.

5. The broadband angle-selective surface based on dual-layer coupling according to any one of claims 1 to 4, characterized in that, The angle selection surface unit has a square cross section. The Jerusalem cross-shaped perforation structure has a long groove vertically connected to the end of each arm. The long side of the long groove is parallel to the edge of the unit. The remaining part of each arm has the same perforation width as the long groove.

6. The broadband angle-selective surface based on dual-layer coupling according to claim 5, characterized in that, The cross-sectional side length of the angle-selected surface unit is 10mm, the thickness of the intermediate air layer (2) is 11mm, the length of the pores parallel to the edge of the Jerusalem cross pore structure is 3.9mm, and the width is 0.5mm; the width of the frame-shaped pores above the Jerusalem cross pore structure is 0.8mm, the width of the remaining pores is 0.5mm, and the overall length of the Jerusalem cross pore structure is 9mm.

7. The broadband angle-selective surface based on dual-layer coupling according to claim 1, characterized in that, The broadband angle-selective surface exhibits dual-polarized wave transmission performance under electromagnetic wave incident at 0°~20°, |S 21 |< −1dB; produces band-stop performance under oblique incidence greater than 50° and maintains |S under oblique incidence at 80°. 21 |< −20dB.

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