Dual-polarization broadband angle selection surface structure for same-frequency anti-interference

Abstract

The invention belongs to the technical field of electromagnetic wave regulation and control and anti-interference, and particularly provides a dual-polarization broadband angle selection surface structure for same-frequency anti-interference, which is used for solving the key technical problems of insufficient angle selectivity, limited working bandwidth, poor polarization adaptability and the like of the existing angle selection structure in engineering application. According to the invention, a structural design of multilayer metal and polystyrene foam based on Jerusalem cross gaps is proposed, and a TE and TM dual-polarization working mode is realized through an innovative unit design and an interlayer coupling mechanism; the multi-layer metal arrangement realizes excellent angle selectivity and more than 6% of working bandwidth while maintaining a low profile, can maintain low-loss transmission of incident waves under small-angle incidence, and can maintain stable angle selectivity and interference suppression performance under large-angle incidence; moreover, the antenna has the remarkable advantages of good angle selectivity, wide working bandwidth, high polarization adaptability, high structural stability and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave control and anti-interference, and specifically provides a dual-polarization broadband angle-selective surface structure for same-frequency anti-interference. Background Art

[0002] In modern wireless communications and satellite navigation, co-channel interference has become a key bottleneck restricting the improvement of system performance. Traditional anti-interference technologies based on frequency domain or time domain are difficult to effectively solve the problem of co-frequency and co-polarization interference. The angle selection technology based on spatial domain provides a new technical path to solve this problem.

[0003] At present, the main technical routes for achieving angle selection still have obvious limitations. First, although the design based on the Brewster angle can achieve good angular selectivity, the structural cross-section height often exceeds ten working wavelengths, which seriously restricts its application in compact equipment. Secondly, although the design using odd-mode resonance or multi-resonance mode can reduce the cross-section height, it usually only supports single-polarization working mode and cannot meet the dual-polarization requirements of modern communication systems. Furthermore, although the design based on 3D structure can expand the working bandwidth, it often has the defects of poor angular selectivity and excessive transition bandwidth. In addition, although the multi-layer FSS structure has improved the angular selectivity to a certain extent, the existing designs generally have the problems of narrow working bandwidth and a sharp deterioration of interference suppression effect when TM polarized waves are incident at large angles. These technical bottlenecks seriously limit the application effect of angle selection structures in actual engineering. Summary of the Invention

[0004] The present invention aims to provide a dual-polarization, broadband, angle-selective surface structure for co-channel interference prevention, addressing key technical challenges faced by existing angle-selective structures in engineering applications, such as insufficient angle selectivity, limited operating bandwidth, and poor polarization adaptability. The present invention proposes a multi-layer metal-plus-polystyrene foam structure based on a Jerusalem cross slot. Through innovative unit cell design and interlayer coupling, it achieves TE and TM dual-polarization operating modes. The multi-layer metal arrangement achieves excellent angle selectivity and an operating bandwidth exceeding 6% while maintaining a low profile (less than two operating wavelengths). It maintains low-loss transmission (<-1dB) for incident waves at low angles of incidence (0° to 15°) and maintains stable angle selectivity and interference suppression performance at high angles of incidence (30° to 75°). Compared to existing technologies, the present invention offers significant advantages, including excellent angle selectivity, wide operating bandwidth, strong polarization adaptability, and high structural stability. Furthermore, the use of metal processing and foam layers ensures low manufacturing cost and excellent reliability, providing a practical engineering solution for co-channel interference prevention applications.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A dual-polarization broadband angle-selective surface structure for co-frequency interference prevention is composed of a number of angle-selective surface units arranged in an array; the angle-selective surface unit includes a lower-layer FSS structure, a first intermediate-layer FSS structure, a second intermediate-layer FSS structure and an upper-layer FSS structure, which are overlapped in sequence from bottom to top, and polystyrene foam layers are filled between adjacent FSS structures; the lower-layer FSS structure, the first intermediate-layer FSS structure, the second intermediate-layer FSS structure and the upper-layer FSS structure all adopt the same structure, and are all metal plates with a Jerusalem cross gap etched along the center; the lower-layer FSS structure and the upper-layer FSS structure adopt the same size, and the first intermediate-layer FSS structure and the second intermediate-layer FSS structure adopt the same size.

[0007] Furthermore, in the lower FSS structure and the upper FSS structure, the gap width of the Jerusalem cross gap is W1, the center gap arm length is L2, and the end loading gap arm length is L1; in the first intermediate layer FSS structure and the second intermediate layer FSS structure, the gap width of the Jerusalem cross gap is W2, the center gap arm length is L4, and the end loading gap arm length is L3; then L2>L1, L4>L3, W1>W2.

[0008] Furthermore, the thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate FSS structure, and between the upper FSS structure and the second intermediate FSS structure is the same.

[0009] Furthermore, the side length P of the angle selection surface unit is 45 mm.

[0010] Furthermore, in the lower FSS structure and the upper FSS structure, the Jerusalem cross gap width W1 is 5.3 mm, the center gap arm length L2 is 36 mm, and the end loading gap arm length L1 is 20 mm.

[0011] Furthermore, in the first intermediate layer FSS structure and the second intermediate layer FSS structure, the Jerusalem cross gap width W2 = 2 mm, the center gap arm length L4 = 35 mm, and the end loading gap arm length L3 = 21.5 mm.

[0012] Furthermore, the thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate FSS structure, and between the upper FSS structure and the second intermediate FSS structure is H1, H1=49mm; the thickness of the polystyrene foam layer between the first intermediate FSS structure and the second intermediate FSS structure is H2=51.3mm.

[0013] Furthermore, the lower layer FSS structure, the first intermediate layer FSS structure, the second intermediate layer FSS structure and the upper layer FSS structure are all made of aluminum plates, and the thickness of the aluminum plates is h=0.25 mm.

[0014] Based on the above technical solution, the beneficial effects of the present invention are:

[0015] The present invention provides a dual-polarization broadband angle-selective surface structure for co-channel interference prevention. This structure uses an innovative multi-layer metal periodic array design to precisely control the transmission characteristics of electromagnetic waves, effectively suppressing co-channel interference signals in complex electromagnetic environments. Its core operating principle can be elaborated as follows:

[0016] When electromagnetic waves are incident at an arbitrary angle of incidence, θ, the structure can independently control both TE-polarized (electric field along the x-axis) and TM-polarized (magnetic field along the y-axis) electromagnetic waves. Under normal incidence, the structure exhibits excellent broadband transmission characteristics, with an operating bandwidth exceeding 6% of the center frequency. Under oblique incidence, a unique electromagnetic resonance mechanism significantly reflects co-channel interference signals within a specific frequency band, achieving joint spatial-frequency filtering. The structure utilizes a multi-layer Jerusalem cross slot array design. Through precisely optimized unit structure and interlayer spacing, it achieves broadband operation with a cross-section less than two operating wavelengths. Based on equivalent circuit model analysis, the structure can be equivalent to a frequency-dependent variable susceptance network, whose impedance characteristics exhibit adaptive adjustment characteristics with changes in the incident angle: at normal incidence, it is matched, achieving efficient transmission; at oblique incidence, it is mismatched, resulting in interference reflection. This intelligent impedance control mechanism is the core of the structure's co-channel interference suppression.

[0017] Compared with the existing technology, the innovation of the present invention is mainly reflected in the following aspects: First, it adopts a metallized design and abandons the traditional dielectric substrate, which not only has a higher power capacity, but also significantly improves the environmental stability and can maintain stable performance in a wide temperature range; secondly, through the innovative multi-layer Jerusalem cross slot unit optimization structure, while maintaining a low profile, dual-polarization broadband operation is achieved, and its working bandwidth covers 3.2-3.4GHz, which fully meets the current communication anti-interference requirements; thirdly, the unique impedance gradient characteristic ensures that stable interference suppression performance can be maintained at large angles of incidence (within the range of 30° to 75°), and the angular selectivity is significantly improved compared to traditional structures. In addition, the structure adopts a completely passive design, avoiding the phase noise and additional interference introduced by active devices. Its insertion loss is less than 1dB, and the out-of-band suppression ratio is better than 20dB. In practical applications, the structure can be easily integrated into the surface of the antenna cover or radar array, and is particularly suitable for application scenarios such as 5G communications, satellite navigation, and airborne radar that have strict requirements for co-channel interference suppression. Test results show that in complex electromagnetic environments, this structure can improve the system's anti-interference capability by more than 15dB, providing an innovative solution to the co-channel interference problem faced by modern wireless systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a structural schematic diagram of the dual-polarization broadband angle selection surface structure for co-frequency anti-interference in the present invention.

[0019] Figure 2 This is a schematic diagram of the unit structure of the dual-polarization broadband angle selection surface structure used for co-frequency anti-interference in the present invention.

[0020] Figure 3 This is a transmission coefficient curve diagram of the incident wave under TE mode at different incident angles of the present invention.

[0021] Figure 4 This is a transmission coefficient curve diagram of the incident wave at different incident angles in the TM mode of the present invention.

[0022] Figure 5 1 is an angle selection performance curve diagram of the present invention in TE polarization mode and TM polarization mode. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0024] In order to facilitate those skilled in the art to fully understand the technical solution of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings. It should be noted that the following examples are only used to illustrate the technical principles and implementation methods of the present invention, and do not constitute any limitation to the scope of protection of the present invention. Based on the basic principles of the present invention, any equivalent transformations or improvements made by those skilled in the art without paying creative labor should be included in the scope of protection of the present invention. In the specific description process, in order to avoid the redundant description of common knowledge affecting the understanding of the core technology of the present invention, some conventional technical details will be appropriately omitted.

[0025] The accompanying drawings of the embodiments of the present invention show schematic diagrams of the relevant structures. It should be noted that the illustrated contents are not drawn strictly to scale, some details are appropriately enlarged for clarity, and some non-critical details may be simplified. The functional areas, structural layers and their relative sizes and positional relationships shown in the figures are only schematic in nature. Reasonable deviations may exist in actual implementation due to process tolerances or technical conditions. Those skilled in the art can adaptively adjust the shape, size and spatial layout of the illustrated structure according to specific application requirements, and these reasonable variations should all fall within the scope of protection of the present invention.

[0026] Specifically, this embodiment provides a dual-polarization broadband angle selection surface structure for co-frequency anti-interference, the structure of which is as follows: Figure 1 As shown, it is composed of 100 angle selection surface units spliced in a 10×10 array; the angle selection surface units are as follows Figure 2 As shown, it includes a lower FSS structure, a first intermediate layer FSS structure, a second intermediate layer FSS structure and an upper FSS structure which are overlapped in sequence from bottom to top, and polystyrene foam layers are filled between adjacent FSS structures; the lower FSS structure, the first intermediate layer FSS structure, the second intermediate layer FSS structure and the upper FSS structure all adopt the same structure, specifically a metal plate with a Jerusalem cross gap etched along the center; the lower FSS structure and the upper FSS structure adopt the same size, and the first intermediate layer FSS structure and the second intermediate layer FSS structure adopt the same size, and the size includes the size of the metal plate and the size of the Jerusalem cross gap.

[0027] Furthermore, the side length of the angle selection surface unit is P=45 mm, that is, the side lengths of the lower FSS structure, the first intermediate FSS structure, the second intermediate FSS structure and the upper FSS structure are all P.

[0028] Furthermore, the lower layer FSS structure, the first intermediate layer FSS structure, the second intermediate layer FSS structure and the upper layer FSS structure are all made of aluminum plates, and the thickness of the aluminum plates is h=0.25 mm.

[0029] Furthermore, in the lower FSS structure and the upper FSS structure, the gap width of the Jerusalem cross gap is W1 = 5.3 mm, the center gap arm length is L2 = 36 mm, and the end loading gap arm length is L1 = 20 mm.

[0030] Furthermore, in the first intermediate layer FSS structure and the second intermediate layer FSS structure, the gap width of the Jerusalem cross gap is W2 = 2 mm, the center gap arm length is L4 = 35 mm, and the end loading gap arm length is L3 = 21.5 mm.

[0031] Furthermore, the thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate layer FSS structure is H1=49 mm, and the thickness of the polystyrene foam layer between the upper FSS structure and the second intermediate layer FSS structure is H1=49 mm, that is, the thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate layer FSS structure and between the upper FSS structure and the second intermediate layer FSS structure is the same; the thickness of the polystyrene foam layer between the first intermediate layer FSS structure and the second intermediate layer FSS structure is H2=51.3 mm.

[0032] The beneficial effects of the present invention are described in detail below in conjunction with simulation tests.

[0033] Based on the finite element commercial electromagnetic simulation software ANSYS Electronics 2021R1, the transmission coefficient of the dual-polarization broadband angle-selective surface structure in the implementation case under the TE polarization mode at different incident angles is simulated and calculated. The results are as follows Figure 3 shown.

[0034] Based on the finite element commercial electromagnetic simulation software ANSYS Electronics 2021R1, the transmission coefficient of the dual-polarization broadband angle-selective surface structure in the implementation case under the TM polarization mode at different incident angles is simulated and calculated. The results are as follows Figure 4 shown.

[0035] Based on the finite element commercial electromagnetic simulation software ANSYS Electronics 2021R1, the angle selection performance of the dual-polarization broadband angle selection surface structure in the implementation case under TE polarization mode and TM polarization mode was simulated and calculated. The results are as follows Figure 5 shown.

[0036] like Figure 3As shown, the horizontal axis represents frequency and the vertical axis represents transmission coefficient. It can be seen from the simulation result graph that the transmission characteristic curve of the structure is in the working center frequency band of 3.3GHz. When the incident angle θ of the TE polarized electromagnetic wave is near 0°, the transmission coefficient varies from 0dB to -1dB, realizing the passband characteristic; when the incident angle θ of the TE polarized electromagnetic wave is ≥30°, the transmission coefficient varies from -20dB to -100dB, realizing the band-stop characteristic, which can be explained that the present invention has good angular selectivity.

[0037] like Figure 4 As shown, the horizontal axis represents frequency and the vertical axis represents transmission coefficient. It can be seen from the simulation result graph that the transmission characteristic curve of the structure is in the working center frequency band of 3.3 GHz. When the incident angle θ of the TM polarized electromagnetic wave is near 0°, the transmission coefficient varies from 0 dB to -1 dB, realizing the passband characteristic; when the incident angle θ of the TM polarized electromagnetic wave is ≥30°, the transmission coefficient varies from -20 dB to -100 dB, realizing the band-stop characteristic, which can illustrate that the present invention has good angular selectivity.

[0038] like Figure 5 As shown in the figure, the horizontal axis represents the frequency and the vertical axis represents the transmission coefficient. It can be seen from the simulation result graph that when the transmission coefficient characteristic curve of the structure is in the operating frequency band of 3.2GHz to 3.4GHz, the electromagnetic wave realizes a bandpass characteristic change from 0dB to -1dB within the incident angle range of -15° to +15°, and at the same time realizes a band-stop characteristic change from -20dB to -120dB within the incident angle range of -30° to -75° and +30° to +75°, and has good angular selectivity in both vertical and horizontal polarization directions.

[0039] In summary, the present invention provides a dual-polarization broadband angle selection surface structure for co-frequency interference prevention. It is implemented based on a frequency selection surface structure with a passive structure, and can achieve good angle selectivity in the vertical polarization and horizontal polarization directions. Different operating frequency bands can be achieved by adjusting the structural dimensions, thereby expanding the scope of application. Compared with other co-frequency interference prevention technologies, the system structure is simple, and no redundant active structure is introduced. While resisting co-frequency interference, no additional interference sources are introduced. Moreover, the dual-polarization angle selection surface of the present invention adopts an all-metal design, with good applicability, high reliability and low price.

[0040] The above description is only a specific embodiment of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes; all disclosed features, or all steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A dual-polarization broadband angle-selective surface structure for co-frequency interference prevention, comprising a plurality of angle-selective surface units arranged in an array; characterized in that: The angle selection surface unit includes a lower FSS structure, a first intermediate layer FSS structure, a second intermediate layer FSS structure and an upper FSS structure, which are overlapped in sequence from bottom to top, and polystyrene foam layers are filled between adjacent FSS structures; the lower FSS structure, the first intermediate layer FSS structure, the second intermediate layer FSS structure and the upper FSS structure all adopt the same structure, and are all metal plates with a Jerusalem cross gap etched along the center; the lower FSS structure and the upper FSS structure adopt the same size, and the first intermediate layer FSS structure and the second intermediate layer FSS structure adopt the same size.

2. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: In the lower layer FSS structure and the upper layer FSS structure, the gap width of the Jerusalem cross gap is W1, the center gap arm length is L2, and the end loading gap arm length is L1; in the first intermediate layer FSS structure and the second intermediate layer FSS structure, the gap width of the Jerusalem cross gap is W2, the center gap arm length is L4, and the end loading gap arm length is L3; then L2>L1, L4>L3, W1>W2.

3. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: The thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate FSS structure, and between the upper FSS structure and the second intermediate FSS structure is the same.

4. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: The side length P of the angle selection surface unit is 45 mm.

5. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: In the lower FSS structure and the upper FSS structure, the Jerusalem cross gap has a gap width W1 = 5.3 mm, a center gap arm length L2 = 36 mm, and an end loading gap arm length L1 = 20 mm.

6. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: In the first intermediate layer FSS structure and the second intermediate layer FSS structure, the Jerusalem cross gap has a gap width W2 = 2 mm, a center gap arm length L4 = 35 mm, and an end loading gap arm length L3 = 21.5 mm.

7. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: The thickness of the polystyrene foam layer between the lower FSS structure and the first intermediate FSS structure, and between the upper FSS structure and the second intermediate FSS structure is H1, H1=49mm; the thickness of the polystyrene foam layer between the first intermediate FSS structure and the second intermediate FSS structure is H2=51.3mm.

8. The dual-polarization broadband angle-selective surface structure for co-frequency anti-interference according to claim 1, characterized in that: The lower layer FSS structure, the first intermediate layer FSS structure, the second intermediate layer FSS structure and the upper layer FSS structure are all made of aluminum plates, and the thickness of the aluminum plates is h=0.25 mm.

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