W-band polarization insensitive wave-absorbing metamaterial structure

Abstract

The invention discloses a W-band polarization insensitive wave-absorbing metamaterial structure, which is characterized by comprising a thin film layer, a dielectric layer arranged on the thin film layer and a metal patch pattern layer arranged on the dielectric layer, and two types of metal patches with various sizes are laid on the surface of the metal patch pattern layer. Metal patches in the metal patch pattern layer are rotationally and symmetrically distributed and arranged around the center of the metal patch pattern layer according to a space group, by changing the thickness of the dielectric layer and the sizes of the metal patches, the wave-absorbing metamaterial structure absorbs electromagnetic waves of a specific frequency band and reduces echoes, and the dielectric layer is made of an FR-4 material with the thickness smaller than 0.18 mm; the preparation method has the advantages that the requirements of low cost, light weight, broadband absorption and high flexibility are met.

Description

Technical Field

[0001] The present invention relates to the field of imaging and electromagnetic communication, and in particular to a W-band polarization-insensitive wave-absorbing metamaterial structure. Background Art

[0002] With the rapid development of modern electronic technology, electromagnetic waves are increasingly used in the fields of communications, radar, stealth technology, etc. However, the power density of electronic equipment continues to increase, and the electromagnetic compatibility problem becomes more and more serious. There is an urgent need for an efficient absorbing material to solve the electromagnetic wave interference and radiation problems. Traditional absorbing materials, such as ferrite, barium titanate, metal powder, graphite, silicon carbide, etc., although they can absorb electromagnetic waves to a certain extent, have the disadvantages of narrow absorption band, high density, poor high temperature characteristics, etc., which makes it difficult to meet the requirements of modern electronic equipment for absorbing materials to be "thin, light, wide, strong, and flexible".

[0003] In recent years, absorbing metamaterials, as a new type of absorbing material, have attracted much attention due to their unique absorbing mechanism and excellent absorbing performance. Absorbing metamaterials are a sub-wavelength artificial periodic structure that can achieve strong absorption of electromagnetic waves by regulating the structure and arrangement of the constituent units. Compared with traditional absorbing materials, absorbing metamaterials have the characteristics of perfect absorption, thin thickness, and light weight, and are expected to surpass traditional materials in broadband absorbing performance.

[0004] The W band (75-110GHz) is located in the millimeter wave frequency band, and has the characteristics of high resolution and high data transmission rate. It is widely used in radar, satellite communication, millimeter wave imaging and other fields. In recent years, there have been some studies on broadband absorbing materials in the W band. The main preparation methods and research results can be divided into the following categories: The first category is to use carbon composite materials to obtain broadband millimeter wave absorbers. For example, the paper "Suda Y, Matsuo R, Yoshii T, et al. Electromagnetic wave absorption properties of carbon nanocoil composites in the millimeterwaveband[C] / / AIP Conference Proceedings. AIP Publishing, 2018, 1929(1)" disperses carbon nanocoil (CNC) composites into epoxy resin or paraffin, and then solidifies the dripped solution on an aluminum substrate to make an absorbing material. The research results show that the absorbing material can effectively absorb waves in the two frequency bands of (18-23) GHz and (70-88) GHz. In addition, some researchers have used porous carbon made of rice husks and soybean husks to prepare absorbers with an absorption efficiency of >90% in the range of (75-110) GHz and a relative bandwidth of about 38%. The second type is to use three-dimensional structures, which can also achieve broadband millimeter wave absorption. For example, the broadband millimeter wave absorber with gradient refractive index printed by 3D printing can keep the reflectivity below -10dB in the ultra-wideband range of (10-200) GHz; some researchers have prepared broadband absorbers with U-shaped three-dimensional metal sheets, which can work in the (60.4-100) GHz frequency band. The above schemes have achieved good absorbing effects in their respective application backgrounds, but the general process is more complicated and the manufacturing cost is higher. The complex three-dimensional structure may also lead to a thicker overall thickness of the absorber, thereby affecting the absorbing performance and flexibility, making it difficult to meet the requirements of low cost, lightweight, broadband absorption and high flexibility. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing W-band absorbing metamaterials are difficult to meet the requirements of low cost, light weight, broadband absorption and high flexibility.

[0006] The present invention solves the above technical problems through the following technical means: a W-band polarization-insensitive absorbing metamaterial structure, comprising a thin film layer, a dielectric layer arranged on the thin film layer, and a metal patch pattern layer arranged on the dielectric layer, the surface of the metal patch pattern layer is flattened with two types and multiple sizes of metal patches, the metal patches in the metal patch pattern layer are distributed and arranged according to the rotational symmetry of the space group with the center of the metal patch pattern layer, by changing the thickness of the dielectric layer and the size of the metal patch, the absorbing metamaterial structure absorbs electromagnetic waves in a specific frequency band and reduces echoes, and the dielectric layer adopts FR-4 material with a thickness of less than 0.18 mm.

[0007] The surface of the metal patch pattern layer of the present invention is flatly paved with two types of metal patches of multiple sizes. By changing the thickness of the dielectric layer and the size of the metal patches, the absorbing metamaterial structure absorbs electromagnetic waves in a specific frequency band and reduces echoes. When the incident wave vertically irradiates the metal patch pattern layer of the absorbing metamaterial structure, a large number of opposite charges are induced on the upper and lower surfaces of the metal patches, thereby exciting an electric response in the metal patch structure. This electric response is coupled with the reverse charge on the thin film layer to induce a magnetic response, resulting in a trough in the reflectivity spectrum corresponding to an absorption peak. Through the spatial layout and size setting of the metal patches, the superposition of multiple such absorption peaks is achieved to achieve broadband absorption, and the overall structure is simple, low cost and lightweight. At the same time, the dielectric layer adopts FR-4 material with a thickness of less than 0.18 mm. The extremely thin thickness allows it to be easily bent, thereby achieving flexibility of the absorber. Therefore, the entire structure meets the requirements of low cost, lightweight, broadband absorption and high flexibility.

[0008] Furthermore, when the incident wave is irradiated vertically to the metal patch pattern layer of the absorbing metamaterial structure, a large number of opposite charges will be induced on the upper and lower surfaces of the metal patch, thereby stimulating an electric response in the metal patch structure. This electric response is coupled with the reverse charge on the thin film layer, inducing a magnetic response, resulting in a trough in the reflectivity spectrum, corresponding to an absorption peak. The superposition of multiple such absorption peaks can be achieved by spatial layout and size setting of the metal patches.

[0009] Furthermore, the metal patch pattern layer is provided with two square patches of different sizes, named S1 and S2, and nine rectangular patches of different sizes, named R1, R2, R3, R4, R5, R6, R7, R8, and R9.

[0010] Furthermore, the metal patch pattern layer is divided into four identical surface units, and the entire metal patch pattern layer is composed of a surface unit with the center of the W-band polarization-insensitive absorbing metamaterial structure at The angle is rotated three times, so that the metal patches in the metal patch pattern layer are distributed and arranged according to the rotational symmetry of the space group with the center of the metal patch pattern layer; in each surface unit, the first row is respectively arranged with S1, S2, S2, S1, and a 90° angle of each metal patch is facing upward and the diagonals are on a line, the second row is respectively arranged with S2, R7, R4, S2 and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the third row is respectively arranged with S2, R2, R7, S2 and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the fourth row is respectively arranged with S1, S2, S2, S1 and they are respectively aligned with S1, S2, S2, S1 in the first row in the vertical direction, and in the first row from left to right between S1 and S2, between S2 and S2, and between S2 and S1 There are first gaps below each of them, with a total of three first gaps, in which R9, R8 and R5 are respectively set, and a 90° angle of each metal patch faces upward; in the second row, there are second gaps below S1 and R7, between R7 and R4, and between R4 and S2 from left to right, with a total of three second gaps, in which R6, R3 and R8 are respectively set, and a 90° angle of each metal patch faces upward; in the third row, there are third gaps below S1 and S2, between S2 and R7, and between R7 and S2 from left to right, with a total of three third gaps, in which R1, R6 and R9 are respectively set, and a 90° angle of each metal patch faces upward; each surface unit overlaps with the metal patch at the edge position of its adjacent surface unit.

[0011] Furthermore, the side lengths of S1 and S2 are 0.68 mm and 0.52 mm respectively.

[0012] Furthermore, the lengths of R1, R2, R3, R4, R5, R6, R7, R8, and R9 are 0.73mm, 0.55mm, 0.46mm, 0.72mm, 0.77mm, 0.76mm, 0.68mm, 0.74mm, and 0.58mm, respectively, and the corresponding widths are 0.7mm, 0.52mm, 0.82mm, 0.56mm, 0.56mm, 0.85mm, 0.53mm, 0.72mm, and 0.56mm, respectively;

[0013] Furthermore, the size of the surface unit is 8.64 mm x 8.64 mm.

[0014] Furthermore, the materials of the film layer and the metal patch pattern layer have an electrical conductivity of σ = 5.8x10 7 S / m copper, thickness is 0.018mm.

[0015] Furthermore, the material of the dielectric layer is epoxy glass fiber board FR-4 material with a dielectric constant of 4.4, a loss tangent of 0.03 and a thickness of less than 0.18 mm.

[0016] Furthermore, the overall thickness of the absorbing metamaterial structure is 0.22 mm. The overall thickness is greater than the sum of the thicknesses of the film layer, the metal patch pattern layer and the dielectric layer because there are still some material errors and process errors in actual applications.

[0017] The advantages of the present invention are:

[0018] (1) The surface of the metal patch pattern layer of the present invention is flatly paved with two types of metal patches of various sizes. By changing the thickness of the dielectric layer and the size of the metal patches, the absorbing metamaterial structure absorbs electromagnetic waves in a specific frequency band and reduces echoes. When the incident wave is vertically irradiated to the metal patch pattern layer of the absorbing metamaterial structure, a large number of opposite charges are induced on the upper and lower surfaces of the metal patches, thereby exciting an electric response in the metal patch structure. This electric response is coupled with the reverse charge on the thin film layer to induce a magnetic response, resulting in a trough in the reflectivity spectrum corresponding to an absorption peak. By spatially arranging and setting the size of the metal patches, multiple such absorption peaks are superimposed to achieve broadband absorption. The overall structure is simple, low cost and lightweight. At the same time, the dielectric layer adopts FR-4 material with a thickness of less than 0.18 mm. The extremely thin thickness allows it to be easily bent, thereby achieving flexibility of the absorber. Therefore, the entire structure meets the requirements of low cost, lightweight, broadband absorption and high flexibility.

[0019] (2) The special arrangement of the metal patches in the metal patch pattern layer of the present invention enables the structure to exhibit polarization insensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a W-band polarization-insensitive absorbing metamaterial disclosed in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the layout of a metal patch pattern layer in a W-band polarization-insensitive absorbing metamaterial structure disclosed in an embodiment of the present invention;

[0022] Figure 3 A simulated absorption spectrum of a TE wave at vertical incidence for a W-band polarization-insensitive absorbing metamaterial structure disclosed in an embodiment of the present invention;

[0023] Figure 4 The simulated absorption spectra of a W-band polarization-insensitive absorbing metamaterial structure disclosed in an embodiment of the present invention for TM waves with different incident angles and different frequencies;

[0024] Figure 5The simulated absorption spectrum of a W-band polarization-insensitive absorbing metamaterial structure disclosed in an embodiment of the present invention for electromagnetic waves with different polarization angles;

[0025] Figure 6 The measured reflection spectrum of a W-band polarization-insensitive absorbing metamaterial structure for vertically incident electromagnetic waves disclosed in an embodiment of the present invention;

[0026] Figure 7 Absorption spectra of a W-band polarization-insensitive absorbing metamaterial structure disclosed in an embodiment of the present invention applied on cylinders of different diameters. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are 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.

[0028] like Figure 1 and Figure 2 As shown, the present invention provides a W-band polarization-insensitive absorbing metamaterial structure, including a thin film layer 11, a dielectric layer 12 arranged on the thin film layer 11, and a metal patch pattern layer 13 arranged on the dielectric layer 12. The surface of the metal patch pattern layer 13 is flattened with two types and multiple sizes of metal patches. By changing the thickness of the dielectric layer 12 and the size of the metal patches, the absorbing metamaterial structure absorbs electromagnetic waves in a specific frequency band and reduces echoes. The dielectric layer 12 is made of FR-4 material with a thickness of less than 0.18 mm. The metal patches on the metal patch pattern layer 13 are a periodic structure. Specifically, a number of identical surface units are provided, and the size of each surface unit is 8.64 mm x 8.64 mm. The area of ​​the metal patch pattern layer 13 is the area of ​​the entire absorbing metamaterial structure. In this embodiment, the materials of the thin film layer 11 and the metal patch pattern layer 13 are both of conductivity σ = 5.8x10 7 The dielectric layer 12 is made of FR-4 epoxy glass fiber board with a dielectric constant of 4.4, a loss tangent of 0.03 and a thickness of 0.18 mm.

[0029] According to the effective medium theory, the magnetic permeability μ and dielectric constant ε of the metamaterial are the key factors that determine its performance. At the same time, the reflectivity and transmittance of the material are also affected by the refractive index n and the wave impedance, and these parameters are closely related to the magnetic permeability μ and dielectric constant ε. By adjusting the thickness of the dielectric layer 12, the periodic arrangement of the metal patch pattern layer 13, and the size of the metal patch, the magnetic permeability μ and dielectric constant ε of the absorbing material can be regulated to reach a predetermined value. Figure 2 As shown, the metal patch pattern layer 13 is carefully designed and arranged by 2 kinds of square patches and 9 kinds of rectangular patches. Different metal patches respond to different absorption peaks, and broadband absorption is achieved by superposition of multiple absorption peaks.

[0030] Continue reading Figure 2 The metal patch pattern layer 13 is provided with two square patches of different sizes, named S1 (the first group of square patches) and S2 (the second group of square patches), and nine rectangular patches of different sizes, named R1 (the first group of rectangular patches), R2 (the second group of rectangular patches), R3 (the third group of rectangular patches), R4 (the fourth group of rectangular patches), R5 (the fifth group of rectangular patches), R6 (the sixth group of rectangular patches), R7 (the seventh group of rectangular patches), R8 (the eighth group of rectangular patches), and R9 (the ninth group of rectangular patches). The side lengths of S1 and S2 are 0.68 mm and 0.52 mm respectively. The lengths of R1, R2, R3, R4, R5, R6, R7, R8, and R9 are 0.73mm, 0.55mm, 0.46mm, 0.72mm, 0.77mm, 0.76mm, 0.68mm, 0.74mm, and 0.58mm, respectively, and the corresponding widths are 0.7mm, 0.52mm, 0.82mm, 0.56mm, 0.56mm, 0.85mm, 0.53mm, 0.72mm, and 0.56mm, respectively.

[0031] The periodic structure of the metal patch pattern layer 13 can be divided into four parts along the center of the pattern, and each part rotates around the center of the metal patch layer. (For example, 90°, 180°, 270° and 360°) and then can overlap with the other three parts and itself, and the metal patch pattern is also symmetrical along its diagonal. Specifically, the metal patch pattern layer 13 is divided into 4 identical surface units along the center of the pattern, and in each surface unit, the first row is respectively arranged with S1, S2, S2, S1, and a 90° angle of each metal patch is facing upward while the diagonals are on a line, the second row is respectively arranged with S2, R7, R4, S2, and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the third row is respectively arranged with S2, R2, R7, S2, and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the fourth row is respectively arranged with S1, S2, S2, S1, and they are respectively aligned with S1, S2, S2, S1 in the first row in the vertical direction, and there is a first row between S1 and S2, between S2 and S2, and below S2 and S1 from left to right in the first row. There are three first gaps in total, and R9, R8 and R5 are set in these three first gaps respectively, and a 90° angle of each metal patch faces upward; there are second gaps between S1 and R7, between R7 and R4, and below R4 and S2 from left to right in the second row, and there are three second gaps in total, and R6, R3 and R8 are set in these three second gaps respectively, and a 90° angle of each metal patch faces upward; there are three third gaps in total, and R1, R6 and R9 are set in these three third gaps respectively, and a 90° angle of each metal patch faces upward; each surface unit overlaps with the metal patch at the edge position of its adjacent surface unit. Figure 1 As shown, in this embodiment, only half of S1 and S2 located at the edge of the entire W-band polarization-insensitive absorbing metamaterial structure are cut off, but in actual applications, the following can be selected: Figure 2 The complete area is shown.

[0032] The structure of the present invention can match the impedance with the atmosphere within a specific frequency range, allowing electromagnetic waves within a specific frequency range to pass through, and then be reflected by the bottom layer, and resonate and lose in the intermediate dielectric layer 12 to achieve high absorption. The present invention achieves broadband high absorption, and due to the special arrangement of the metal patch pattern layer 13, polarization insensitivity can be achieved, and the structure is composed of only squares and rectangles, which is convenient for manufacturing.

[0033] The W-band broadband polarization-insensitive material is simulated and calculated by the algorithm in the electromagnetic simulation software. Under the condition of vertical incident electromagnetic waves, the absorption spectrum of the metamaterial structure is as follows: Figure 3 As shown, the calculation formula for the absorption rate is Where S 11 is the simulated value of the reflection coefficient, S21 is the simulated value of the transmission coefficient. When electromagnetic waves are incident, in a specific frequency band, due to the resonance absorption effect of the metamaterial, the reflectivity of the frequency band is close to 0. Since the metal film reflective layer 11 completely reflects the electromagnetic waves, the transmittance is 0, so the final absorption rate is calculated as The final calculated average absorption rate of the material in the range of 75-110 GHz is about 94.3%, and the maximum absorption rate at certain frequencies is as high as 99.99%.

[0034] See also Figure 4 In the embodiment of the present invention, the absorbing material in the embodiment of the present invention is simulated by the finite difference time domain (FDTD) electromagnetic simulation method to observe the absorption performance of the absorbing material for TM waves of different incident angles and different frequency bands. Figure 4 It can be seen that the absorbing material in the embodiment of the present invention has high absorption performance for TM waves in the range of 75-110 GHz, and the average absorption rate reaches more than 94.3%. Moreover, the absorbing material maintains high absorption rate absorption for TM waves in the range of 75-110 GHz at incident angles of 0°, 15°, 30°, 45° and 60°, so the absorbing material in the embodiment of the present invention has wide incident angle stability.

[0035] See also Figure 5 In the embodiment of the present invention, the absorbing material in embodiment 1 is simulated by using the FDTD electromagnetic simulation method to observe the absorption performance of the absorbing material at different polarization angles. Figure 5 It can be seen that the absorbing material in the embodiment has high absorption performance for millimeter waves in the range of 75-110 GHz, and the average absorption rate reaches more than 94.3%. Moreover, when the polarization angles are 0°, 30°, 60° and 90°, the absorption performance of the absorbing material for millimeter waves in the range of 75-110 GHz does not change much, and the high absorption rate is maintained. Therefore, the absorbing material in the embodiment has polarization insensitivity.

[0036] See also Figure 6 In the embodiment of the present invention, the absorbing material in the embodiment is tested for its absorption performance of vertically incident electromagnetic waves in a plane. Figure 6 It can be seen that the absorbing material in the embodiment has an absorption rate of more than 93% for electromagnetic waves in the frequency band of 75-110 GHz.

[0037] See also Figure 7 In the embodiment of the present invention, the absorbing material in the embodiment of the present invention is attached to cylinders with diameters of 66 mm, 82 mm, 110 mm and 130 mm respectively, and the absorbing performance of the absorbing material with different bending degrees is experimentally measured. Figure 7It can be seen that the cylinder coated with the absorbing material still maintains a high absorption rate for electromagnetic waves in the range of 75-110 GHz. Therefore, the absorbing material in this embodiment has good flexibility and has the performance of maintaining a high absorption rate at a bending angle.

[0038] Through the above technical solution, the W-band polarization-insensitive absorbing metamaterial structure provided by the present invention, when the incident wave is vertically irradiated to the metal patch pattern layer 13 of the metamaterial, will induce a large number of opposite charges on the upper and lower surfaces of the metal patch, thereby stimulating a clear electrical response in the metal patch structure. This electrical response is strongly coupled with the reverse charge on the thin film layer 11, further inducing a magnetic response, resulting in a significant trough in the reflectivity spectrum, corresponding to an ideal absorption peak. In addition, by carefully designing the following Figure 2 The rotationally symmetrical arrangement and multi-size structure shown achieve the superposition of multiple such absorption peaks, thereby broadening the working bandwidth. Thanks to this special arrangement, the structure exhibits polarization insensitivity. 0.18 mm FR-4 is used as the dielectric layer 12. Its extremely thin thickness allows it to be easily bent, making the absorber flexible. The absorbing material is mass-produced through a printed circuit board printing process, which helps to achieve low-cost large-scale applications. In summary, the overall structure can achieve broadband absorption in the W band, and has high absorption rate, wide incident angle stability and polarization insensitivity to electromagnetic waves in the W band. Moreover, the absorbing material is ultra-thin, light and has good flexibility, and can be bent into a curved surface for application in actual devices, thus having high practical value.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, 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 invention.

Claims

1. A W-band polarization-insensitive absorbing metamaterial structure, characterized in that: The invention comprises a thin film layer, a dielectric layer arranged on the thin film layer, and a metal patch pattern layer arranged on the dielectric layer. The surface of the metal patch pattern layer is flattened with two types of metal patches of multiple sizes. The metal patches in the metal patch pattern layer are distributed and arranged according to the rotational symmetry of the space group with the center of the metal patch pattern layer. By changing the thickness of the dielectric layer and the size of the metal patches, the absorbing metamaterial structure absorbs electromagnetic waves in a specific frequency band and reduces echoes. The dielectric layer adopts FR-4 material with a thickness of less than 0.18 mm.

2. The W-band polarization-insensitive absorbing metamaterial structure according to claim 1, characterized in that: When the incident wave is irradiated vertically to the metal patch pattern layer of the absorbing metamaterial structure, a large number of opposite charges will be induced on the upper and lower surfaces of the metal patch, thereby stimulating an electric response in the metal patch structure. This electric response is coupled with the reverse charge on the thin film layer, inducing a magnetic response, resulting in a trough in the reflectivity spectrum, corresponding to an absorption peak. The superposition of multiple such absorption peaks can be achieved by spatial layout and size setting of the metal patches.

3. The W-band polarization-insensitive absorbing metamaterial structure according to claim 2, characterized in that: The metal patch pattern layer is provided with two square patches of different sizes, named S1 and S2, and is also provided with nine rectangular patches of different sizes, named R1, R2, R3, R4, R5, R6, R7, R8, and R9.

4. The W-band polarization-insensitive absorbing metamaterial structure according to claim 3, characterized in that: The metal patch pattern layer is divided into four identical surface units. The entire metal patch pattern layer consists of a surface unit with the center of the W-band polarization-insensitive absorbing metamaterial structure at The angle is rotated three times, so that the metal patches in the metal patch pattern layer are distributed and arranged according to the rotational symmetry of the space group with the center of the metal patch pattern layer; in each surface unit, the first row is respectively arranged with S1, S2, S2, S1, and a 90° angle of each metal patch is facing upward and the diagonals are on a line, the second row is respectively arranged with S2, R7, R4, S2 and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the third row is respectively arranged with S2, R2, R7, S2 and they are respectively aligned with S1, S2, S2, S1 in the vertical direction, the fourth row is respectively arranged with S1, S2, S2, S1 and they are respectively aligned with S1, S2, S2, S1 in the first row in the vertical direction, and in the first row from left to right between S1 and S2, between S2 and S2, and between S2 and S1 There are first gaps below each of them, with a total of three first gaps, in which R9, R8 and R5 are respectively set, and a 90° angle of each metal patch faces upward; in the second row, there are second gaps below S1 and R7, between R7 and R4, and between R4 and S2 from left to right, with a total of three second gaps, in which R6, R3 and R8 are respectively set, and a 90° angle of each metal patch faces upward; in the third row, there are third gaps below S1 and S2, between S2 and R7, and between R7 and S2 from left to right, with a total of three third gaps, in which R1, R6 and R9 are respectively set, and a 90° angle of each metal patch faces upward; each surface unit overlaps with the metal patch at the edge position of its adjacent surface unit.

5. The W-band polarization-insensitive absorbing metamaterial structure according to claim 3, characterized in that: The side lengths of S1 and S2 are 0.68 mm and 0.52 mm respectively.

6. The W-band polarization-insensitive absorbing metamaterial structure according to claim 3, characterized in that: The lengths of R1, R2, R3, R4, R5, R6, R7, R8, and R9 are 0.73mm, 0.55mm, 0.46mm, 0.72mm, 0.77mm, 0.76mm, 0.68mm, 0.74mm, and 0.58mm, respectively, and the corresponding widths are 0.7mm, 0.52mm, 0.82mm, 0.56mm, 0.56mm, 0.85mm, 0.53mm, 0.72mm, and 0.56mm, respectively.

7. The W-band polarization-insensitive absorbing metamaterial structure according to claim 1, characterized in that: The dimensions of the surface unit are 8.64 mm x 8.64 mm.

8. The W-band polarization-insensitive absorbing metamaterial structure according to claim 1, characterized in that: The materials of the film layer and the metal patch pattern layer have an electrical conductivity of σ = 5.8x10 7 S / m copper, thickness is 0.018mm.

9. The W-band polarization-insensitive absorbing metamaterial structure according to claim 1, characterized in that: The material of the dielectric layer is epoxy glass fiber board FR-4 material with a dielectric constant of 4.4, a loss tangent of 0.03 and a thickness of less than 0.18 mm.

10. The W-band polarization-insensitive absorbing metamaterial structure according to claim 1, characterized in that: The overall thickness of the wave-absorbing metamaterial structure is 0.22 mm.

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