An ultra-broadband diffuse reflection metasurface

Abstract

The present invention provides an ultra-wideband diffuse reflection metasurface, which belongs to the technical field of artificial electromagnetic materials. The ultra-wideband diffuse reflection metasurface comprises, from top to bottom, a coding unit, a dielectric plate and a metal grounding layer. The first surface of the dielectric plate is printed with M×N (M≥2, N≥2) periodically arranged coding units, and the second surface of the dielectric plate opposite to the first surface is provided with a metal grounding layer. The ultra-wideband diffuse reflection metasurface of the present invention, through the structural arrangement of the first coding subunit and the second coding subunit, makes the bandwidth of the diffuse reflection metasurface wider, thereby expanding the scope of application.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial electromagnetic materials, and in particular to an ultra-wideband diffuse reflection super surface. Background Art

[0002] Metasurface is a two-dimensional artificial electromagnetic metamaterial that is anisotropic and quasi-periodic on a subwavelength scale. By designing the structure of subwavelength units and adjusting their arrangement in space, the state of electromagnetic waves can be flexibly adjusted, such as achieving free regulation of the amplitude and phase of electromagnetic wave reflection or transmission, and free conversion of polarization mode.

[0003] Common electromagnetic metasurfaces include frequency selective surfaces, electromagnetic bandgap structures, metamaterial absorbers, phase gradient metasurfaces, and diffuse reflective metasurfaces. Diffuse reflective metasurfaces rely on their random reflection phase distribution to randomly distribute the scattered electromagnetic wave energy to various scattering directions without significant scattering main lobes. When used in electromagnetic stealth and other applications, they place higher requirements on RCS reduction and frequency bandwidth.

[0004] In the prior art, the bandwidth of the metasurface cannot meet the requirements of ultra-wideband, which limits the application scope of the metasurface. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the bandwidth of the metasurface in the prior art cannot meet the requirements of ultra-wideband, which limits the application scope of the metasurface, thereby providing an ultra-wideband diffuse reflection metasurface.

[0006] The present invention also provides a method for using the ultra-wideband diffuse reflection metasurface.

[0007] An ultra-wideband diffuse reflection metasurface provided by the present invention comprises, from top to bottom, a coding unit, a dielectric plate and a metal grounding layer;

[0008] The first surface of the dielectric plate is printed with M×N (M≥2, N≥2) periodically arranged encoding units, and the second surface of the dielectric plate opposite to the first surface is provided with a metal grounding layer;

[0009] The encoding unit includes K×K (K≥2) periodically arranged encoding subunits; the encoding unit includes: a first encoding subunit and a second encoding subunit; the number and position of the first encoding subunit and the second encoding subunit on the first surface of the dielectric plate are determined by an optimal encoding sequence;

[0010] The first encoding subunit and the second encoding subunit have a height difference on the dielectric plate;

[0011] The first encoding subunit is a first circular ring with a radius of r1, and the first circular ring is inwardly concave with four first rectangular grooves with a length of L1 and a width of W1; the first rectangular grooves are evenly arranged along the circumferential direction of the first circular ring;

[0012] The second encoding subunit is a second circular ring with a radius of r2. The first circular ring is inwardly recessed with four second rectangular grooves with a length of L2 and a width of W2. The second rectangular grooves are evenly arranged along the circumferential direction of the first circular ring.

[0013] As a preferred solution, the first encoding subunit is arranged on the surface of the dielectric plate; and the second encoding subunit is arranged at one third of the thickness of the dielectric plate.

[0014] As a preferred solution, when the thickness of the dielectric plate is H, a hole with a height of 2 / 3H is dug on the first surface of the dielectric plate; and the second encoding subunit is arranged on the bottom surface of the hole.

[0015] As a preferred solution, both the first rectangular groove and the second rectangular groove are provided with chamfers.

[0016] As a preferred embodiment, the first encoding subunit, the corresponding dielectric plate and the metal grounding layer form a first basic unit; the second encoding subunit, the corresponding dielectric plate and the metal grounding layer form a second basic unit; the size of the first basic unit is consistent with the size of the second basic unit when arranged in 2×2.

[0017] As a preferred solution, one first basic unit and four second basic units arranged in 2×2 form a coding subarray.

[0018] As a preferred solution, in the first encoding subunit, r1 is 3.8 mm, L1 is 2.09 mm, and W1 is 0.5 mm; in the second encoding subunit, r2 is 2.15 mm, L2 is 0.54 mm, and W2 is 0.3 mm.

[0019] As a preferred solution, the side length of the first basic unit is 10 mm; the side length of the second basic unit is 5 mm.

[0020] As a preferred solution, the process of determining the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate by using the optimal coding sequence includes:

[0021] S1: Construct a diffuse reflection metasurface consisting of M×N periodically arranged metasurface units. According to the principle of array antenna pattern superposition, when the incident electromagnetic wave acts on the diffuse reflection metasurface, the far-field scattering field F of the diffuse reflection metasurface is represented by the unit direction function EP and the array factor direction function AF:

[0022] F=EP·AF

[0023]

[0024] where k0 represents the wave number in free space, and d represent the phase response and period of the diffuse reflective metasurface unit, respectively, and θ and Respectively represent the elevation angle and azimuth angle of the reflected electromagnetic wave, θ i and denote the elevation angle and azimuth angle of the incident electromagnetic wave respectively;

[0025] S2: Construct the cost function CostFunction through F, and exhaustively optimize the coding sequence of the diffuse reflective metasurface through CostFunction to obtain the optimal coding sequence, where the expression of CostFunction is:

[0026] CostFunction=min(F max );

[0027] S3: Correspond the binary code "0" in the optimal coding sequence to the first coding subunit, and correspond the binary code "1" to the second coding subunit, to obtain the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The ultra-wideband diffuse reflection metasurface provided by the present invention has a wider bandwidth and a larger application range through the structural setting of the first encoding subunit and the second encoding subunit.

[0030] 2. The ultra-wideband diffuse reflection metasurface provided by the present invention obtains the optimal coding sequence after optimization; the four second basic units are consistent with the first basic unit and have a phase difference of 180 degrees, and the reflection amplitudes of the two basic units are consistent; the basic units are arranged according to the optimized coding sequence to form the entire diffuse reflection metasurface, which diffusely reflects electromagnetic wave energy.

[0031] 3. The ultra-wideband diffuse reflection metasurface provided by the present invention exhaustively optimizes the coding sequence of the diffuse reflection metasurface to obtain the optimal coding sequence. Compared with the prior art, it achieves better RCS reduction characteristics in the ultra-wideband range of 7-29GHz; it can be applied to some application scenarios such as radar target stealth. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the three-dimensional perspective structure of the ultra-wideband diffuse reflection metasurface of the present invention.

[0034] Figure 2 It is a schematic structural diagram of the first encoding subunit and the first dielectric plate of the present invention.

[0035] Figure 3 It is a schematic diagram of the top structure of the first encoding subunit of the present invention.

[0036] Figure 4 It is a schematic structural diagram of the second encoding subunit and the second dielectric plate of the present invention.

[0037] Figure 5 It is a schematic diagram of the top structure of the second encoding subunit of the present invention.

[0038] Figure 6 It is a schematic diagram of the top view structure of the ultra-wideband diffuse reflection metasurface of the present invention.

[0039] Figure 7 Phase response and phase difference diagram of two different encoding structures provided in implementation 1.

[0040] Figure 8 Return loss amplitude diagram of two different coding structures provided in Example 1.

[0041] Fig. 9 This is a simulation diagram of the diffuse reflection beam of the metasurface provided in Example 1 at 8 GHz.

[0042] Fig.10 This is a simulation diagram of the diffuse reflection beam of the metasurface provided in Example 1 at 14 GHZ.

[0043] Fig.11 This is a simulation diagram of the diffuse reflection beam of the metasurface provided in Example 1 at 20 GHZ.

[0044] Fig.12 This is a simulation diagram of the diffuse reflection beam of the metasurface provided in Example 1 at 29 GHZ.

[0045] Fig.13 RCS reduction characteristic diagram of the metasurface provided in Example 1.

[0046] Description of reference numerals:

[0047] 1. Coding unit; 2. Dielectric plate; 3. Metal grounding layer; 4. First coding subunit; 5. First dielectric plate; 6. First circular ring; 7. First rectangular groove; 8. Second coding subunit; 9. Second dielectric plate; 10. Hole; 11. Second circular ring; 12. Second rectangular groove. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] The ultra-wideband diffuse reflection metasurface provided in this embodiment is Figure 1 As shown, it includes, from top to bottom, a coding unit 1, a dielectric plate 2 and a metal grounding layer 3; M×N (M≥2, N≥2) periodically arranged coding units 1 are printed on the first surface of the dielectric plate, and the second surface of the dielectric plate opposite to the first surface is provided with a metal grounding layer 3;

[0053] The material of the dielectric plate 2 is F4B plate, with a dielectric constant of 2.2, a loss tangent of 0.002, and a thickness H of 4.5 mm;

[0054] Specifically, the diffuse reflection metasurface is formed by periodically arranging the first basic unit and the second basic unit;

[0055] like Figure 2 As shown, the first basic unit includes, from top to bottom, a first encoding subunit 4, a first dielectric plate 5 and a first metal grounding layer 3;

[0056] The first encoding subunit 4 is printed on the first surface of the first dielectric plate 5, and the first metal grounding layer 3 is arranged on the second surface of the first dielectric plate 5;

[0057] like Figure 3 As shown, the first encoding subunit 4 is a first circular ring 6 with a radius of r1, and the width of the first circular ring 6 is c1. The first circular ring 6 is recessed inward with four first rectangular grooves 7 with a length of L1 and a width of W1, and a first chamfer is arranged at the end of the first rectangular groove 7; the first rectangular grooves 7 are evenly arranged along the circumferential direction of the first circular ring 6; the specific values ​​are r1 is 3.8mm, L1 is 2.09mm, W1 is 0.5mm, and c1 is 0.5mm; the first chamfer size d1 is 0.5mm.

[0058] like Figure 4 As shown, the second basic unit includes, from top to bottom, a second encoding subunit 8, a second dielectric plate 9 and a second metal grounding layer 3;

[0059] A hole 10 with a height of 3 mm is provided on the first surface of the second dielectric plate 9; the second encoding subunit 8 is arranged at the bottom of the hole 10;

[0060] like Figure 5 As shown, the second encoding subunit 8 is a second circular ring 11 with a radius of r2, the width of the second circular ring 11 is c2, the second circular ring 11 is recessed inwardly with four second rectangular grooves 12 with a length of L2 and a width of W2, and a second chamfer is arranged at the end of the second rectangular groove 12; the second rectangular grooves 12 are evenly arranged along the circumferential direction of the first circular ring 6; the specific values ​​are: r2 is 2.15mm, L2 is 0.54mm, W2 is 0.3mm, c2 is 0.5mm; the first chamfer size d2 is 0.25mm.

[0061] like Figure 6 As shown, the side length of the first basic unit is 10 mm, and the side length of the second basic unit is 5 mm; therefore, the size of the first basic unit is consistent with the size of the second basic unit when arranged in 2×2; one first basic unit and four second basic units arranged in 2×2 form a coding subarray;

[0062] The process of determining the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate by using the optimal coding sequence includes:

[0063] S1: Construct a diffuse reflection metasurface consisting of M×N periodically arranged metasurface units. According to the principle of array antenna pattern superposition, when the incident electromagnetic wave acts on the diffuse reflection metasurface, the far-field scattering field F of the diffuse reflection metasurface is represented by the unit direction function EP and the array factor direction function AF:

[0064] F=EP·AF

[0065]

[0066] where k0 represents the wave number in free space, and d represent the phase response and period of the diffuse reflective metasurface unit, respectively, and θ and Respectively represent the elevation angle and azimuth angle of the reflected electromagnetic wave, θ i and denote the elevation angle and azimuth angle of the incident electromagnetic wave respectively;

[0067] S2: Construct the cost function CostFunction through F, and exhaustively optimize the coding sequence of the diffuse reflective metasurface through CostFunction to obtain the optimal coding sequence, where the expression of CostFunction is:

[0068] CostFunction=min(F max );

[0069] S3: Correspond the binary code "0" in the optimal coding sequence to the first coding subunit, and correspond the binary code "1" to the second coding subunit, to obtain the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate.

[0070] Figure 7 and Figure 8 As shown, the phase response and amplitude response of the two sub-units in the above embodiment are simulated in the range of 4GHZ-28GHZ by using the commercial simulation software HFSS-19.0 and applying the periodic boundary conditions. Figure 7 is a reflection phase curve diagram of two basic units in this embodiment, Figure 8 Graph showing the reflection amplitudes of two basic units in this embodiment.

[0071] like Figure 9-12 As shown, the commercial simulation software HFSS-19.0 is used to simulate and calculate the radar cross section of a single station in the above embodiment when the electromagnetic waves with frequencies of 8 GHZ, 14 GHZ, 20 GHZ, and 29 GHZ are irradiated. Among them: Fig. 9 Schematic diagram of the scattering field of the metasurface in the upper half space of an embodiment of the present invention under irradiation of an electromagnetic wave of 8 GHz; Fig.10 Schematic diagram of the scattering field of the metasurface in the upper half space of an embodiment of the present invention under irradiation of 14 GHz electromagnetic waves; Fig.11 Schematic diagram of the scattering field of the metasurface in the upper half space of an embodiment of the present invention under irradiation of 20 GHz electromagnetic waves; Fig.12 It is a schematic diagram of the scattering field of the metasurface in the upper half space of an embodiment of the present invention under the irradiation of 29 GHZ electromagnetic waves.

[0072] like Fig.13 As shown, when a plane wave is vertically irradiated onto the metasurface of an embodiment of the present invention, an RCS reduction of more than 10 dB is achieved in the frequency band of 11.5 GHz to 29.5 GHz, and the maximum reduction can reach 25 dB, which indicates that the embodiment of the present invention achieves low single-station radar cross-section characteristics in an ultra-wide frequency band.

[0073] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. An ultra-wideband diffuse reflection metasurface, characterized in that: It includes, from top to bottom, a coding unit (1), a dielectric plate (2) and a metal grounding layer (3); The first surface of the dielectric plate is printed with M×N (M≥2, N≥2) periodically arranged encoding units (1), and the second surface of the dielectric plate opposite to the first surface is provided with a metal grounding layer (3); The encoding unit (1) comprises K×K (K≥2) periodically arranged encoding subunits; the encoding unit (1) comprises: a first encoding subunit (4) and a second encoding subunit (8); the number and position of the first encoding subunit (4) and the second encoding subunit (8) on the first surface of the dielectric plate are determined by an optimal encoding sequence; The first encoding subunit (4) and the second encoding subunit (8) have a height difference on the dielectric plate; The first encoding subunit (4) is a first circular ring (6) with a radius of r1, and the first circular ring (6) is inwardly recessed with four first rectangular grooves (7) with a length of L1 and a width of W1; the first rectangular grooves (7) are evenly arranged along the circumferential direction of the first circular ring (6); The second encoding subunit (8) is a second circular ring (11) with a radius of r2, and the first circular ring (6) is inwardly recessed with four second rectangular grooves (12) with a length of L2 and a width of W2; the second rectangular grooves (12) are evenly arranged along the circumferential direction of the first circular ring (6); The thickness of the dielectric plate is H, and a hole (10) with a height of 2 / 3H is dug on the first surface of the dielectric plate; the second encoding subunit (8) is arranged on the bottom surface of the hole (10).

2. The ultra-wideband diffuse reflection metasurface according to claim 1, characterized in that: The first encoding subunit (4) is arranged on the surface of the dielectric plate; the second encoding subunit (8) is arranged at one third of the thickness of the dielectric plate.

3. The ultra-wideband diffuse reflection metasurface according to claim 1, characterized in that: The first rectangular groove (7) and the second rectangular groove (12) are both provided with chamfers.

4. The ultra-wideband diffuse reflection metasurface according to claim 1, characterized in that: The first encoding subunit (4), the dielectric plate corresponding thereto and the metal grounding layer (3) form a first basic unit; the second encoding subunit (8), the dielectric plate corresponding thereto and the metal grounding layer (3) form a second basic unit; the size of the first basic unit is consistent with the size of the second basic unit when arranged in 2×2.

5. The ultra-wideband diffuse reflection metasurface according to claim 4, characterized in that: One first basic unit and four second basic units arranged in 2×2 form a coding subarray.

6. The ultra-wideband diffuse reflection metasurface according to claim 5, characterized in that: In the first encoding subunit (4), r1 is 3.8 mm, L1 is 2.09 mm, and W1 is 0.5 mm; in the second encoding subunit (8), r2 is 2.15 mm, L2 is 0.54 mm, and W2 is 0.3 mm.

7. The ultra-wideband diffuse reflection metasurface according to claim 6, characterized in that: The side length of the first basic unit is 10 mm; the side length of the second basic unit is 5 mm.

8. The ultra-wideband diffuse reflection metasurface according to any one of claims 1 to 7, characterized in that: The process of determining the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate by using the optimal coding sequence includes: S1: Construct a diffuse reflection metasurface consisting of M×N periodically arranged metasurface units. According to the principle of array antenna pattern superposition, when the incident electromagnetic wave acts on the diffuse reflection metasurface, the far-field scattering field F of the diffuse reflection metasurface is represented by the unit direction function EP and the array factor direction function AF: F=EP·AF where k0 represents the wave number in free space, and d represent the phase response and period of the diffuse reflective metasurface unit, respectively, and θ and Respectively represent the elevation angle and azimuth angle of the reflected electromagnetic wave, θ i and denote the elevation angle and azimuth angle of the incident electromagnetic wave respectively; S2: Construct the cost function CostFunction through F, and exhaustively optimize the coding sequence of the diffuse reflective metasurface through CostFunction to obtain the optimal coding sequence, where the expression of CostFunction is: CostFunction=min(F max ); S3: Correspond the binary code "0" in the optimal coding sequence to the first coding subunit, and correspond the binary code "1" to the second coding subunit, to obtain the number and position of the first coding subunit and the second coding subunit on the first surface of the dielectric plate.

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