A full-band three-dimensional wave-absorbing metamaterial

Abstract

The application provides a full-band three-dimensional wave-absorbing metamaterial, comprising a plurality of basic structure units arranged in a periodic array, wherein the basic structure unit comprises a first electromagnetic loss three-dimensional superstructure, a second electromagnetic loss three-dimensional superstructure, a third electromagnetic loss three-dimensional superstructure, a fourth electromagnetic loss three-dimensional superstructure, a fifth electromagnetic loss three-dimensional superstructure, a sixth electromagnetic loss three-dimensional superstructure and a metal back plate arranged in sequence from top to bottom; and a resistive frequency selective surface is loaded on each of the first electromagnetic loss three-dimensional superstructure, the second electromagnetic loss three-dimensional superstructure, the third electromagnetic loss three-dimensional superstructure, the fourth electromagnetic loss three-dimensional superstructure, the fifth electromagnetic loss three-dimensional superstructure and the sixth electromagnetic loss three-dimensional superstructure; the application has the following beneficial effects: the resistive frequency surface, the pure metal patch and the electromagnetic loss three-dimensional superstructure are combined for multi-dimensional coupling absorption design, so that the full-band absorption performance is realized in the L, S, C, X, Ku, K and Ka bands which have a high utilization rate at present, and a certain electromagnetic loss performance is still exhibited in the V and W bands; the thickness is relatively thin, the maximum oblique incidence angle is not less than 70 DEG, so that the demand of a thin-layer, low-area-density electromagnetic wave-absorbing material working in a full-band range at present is met.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorption technology, and in particular to a three-dimensional wave-absorbing metamaterial that covers the entire frequency band. Background Technology

[0002] With the rapid development of wireless communication technology and the widespread application of mobile terminals, the application scope of electromagnetic frequency bands in information transmission is constantly expanding. Taking communication technology as an example, in the development process from 1G to 5G, the operating frequency band has expanded from 800 / 900MHz to over 24GHz. Therefore, in fields such as military, communications, and medicine, full-band electromagnetic interference and pollution have become major problems that urgently need to be solved. Based on this, the development of high-performance full-band electromagnetic absorbing materials has become particularly urgent, as this can not only improve the performance of electronic devices but also effectively reduce the impact of electromagnetic pollution on human health and the environment.

[0003] In existing technologies, low-frequency absorbing materials mainly include ferrites, magnetic composite materials, and magnetic metal powders. While coating absorbing materials prepared based on these materials can achieve narrowband absorption performance with relatively thin thicknesses in the 1–8 GHz frequency band, they suffer from high areal density. To achieve broadband absorption, absorbing structures composed of multi-layered cascaded two-dimensional resistive frequency-selective surfaces are commonly used. However, this design approach still faces several challenges: on the one hand, it is difficult to simultaneously achieve an effective balance between low-frequency and high-frequency absorption performance across the entire frequency band; on the other hand, achieving low-frequency absorption often results in an excessively large overall thickness. Therefore, developing a thin-layer, low-area-density electromagnetic absorbing material that can operate across the entire frequency band while also possessing good oblique incidence stability is a research hotspot to meet the current application needs in the field of electromagnetic absorption. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a full-band three-dimensional absorbing metamaterial to solve the problem that existing absorbing materials are unable to effectively balance the absorption performance of low and high frequencies across the entire frequency band at the same time, and often result in an excessively large overall thickness when achieving low-frequency absorption.

[0005] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0006] A full-band three-dimensional absorbing metamaterial includes several basic structural units arranged in a periodic array. Each basic structural unit comprises, from top to bottom, a first electromagnetic loss three-dimensional metastructure, a second electromagnetic loss three-dimensional metastructure, a third electromagnetic loss three-dimensional metastructure, a fourth electromagnetic loss three-dimensional metastructure, a fifth electromagnetic loss three-dimensional metastructure, a sixth electromagnetic loss three-dimensional metastructure, and a metal backplate. The first electromagnetic loss three-dimensional metastructure has a first resistive frequency selective surface; the second electromagnetic loss three-dimensional metastructure has a second resistive frequency selective surface; the third electromagnetic loss three-dimensional metastructure has a third resistive frequency selective surface; the fourth electromagnetic loss three-dimensional metastructure has a fourth resistive frequency selective surface; the fifth electromagnetic loss three-dimensional metastructure has a fifth resistive frequency selective surface; and the sixth electromagnetic loss three-dimensional metastructure has a sixth resistive frequency selective surface and a seventh resistive frequency selective surface.

[0007] In one embodiment of the present invention, the first electromagnetic loss three-dimensional superstructure, the second electromagnetic loss three-dimensional superstructure, the third electromagnetic loss three-dimensional superstructure, the fourth electromagnetic loss three-dimensional superstructure, the fifth electromagnetic loss three-dimensional superstructure and the sixth electromagnetic loss three-dimensional superstructure are all made of materials that can be used in 3D printing or flatbed engraving processes and have certain magnetic loss or dielectric loss characteristics.

[0008] In one embodiment of the present invention, the first electromagnetic loss three-dimensional superstructure includes a top plate and a first hollow column installed on the bottom side of the top plate, the bottom side of the first hollow column being connected to the second electromagnetic loss three-dimensional superstructure; the first resistive frequency selection surface is located in the first hollow column and connected to the top plate, and the first resistive frequency selection surface is a square uniform sheet resistance film.

[0009] In one embodiment of the present invention, the second electromagnetic loss three-dimensional superstructure includes a second hollow column connected to the third electromagnetic loss three-dimensional superstructure and a first support member installed inside the top side of the second hollow column, the top side of the first support member being connected to the first electromagnetic loss three-dimensional superstructure; the second resistive frequency selection surface is installed on the side of the first support member away from the first electromagnetic loss three-dimensional superstructure, and the second resistive frequency selection surface is also a square uniform sheet resistance film.

[0010] In one embodiment of the present invention, the third electromagnetic loss three-dimensional superstructure includes a third hollow column connected to the fourth electromagnetic loss three-dimensional superstructure and a second support member installed inside the top side of the third hollow column; the third resistive frequency selection surface is installed on the top side of the third hollow column and the second support member, and the third hollow column is connected to the second electromagnetic loss three-dimensional superstructure through the third resistive frequency selection surface, wherein the third resistive frequency selection surface is a grid-shaped uniform sheet resistance film.

[0011] In one embodiment of the present invention, the fourth electromagnetic loss three-dimensional superstructure includes a fourth hollow column connected to a fifth electromagnetic loss three-dimensional superstructure and a third support member installed inside the top side of the fourth hollow column; the fourth resistive frequency selection surface is installed on the top side of the fourth hollow column and the third support member, and the fourth hollow column is connected to the third electromagnetic loss three-dimensional superstructure through the fourth resistive frequency selection surface, wherein the fourth resistive frequency selection surface is a square annular uniform sheet resistance film.

[0012] In one embodiment of the present invention, the fifth electromagnetic loss three-dimensional superstructure includes a fifth hollow column connected to the sixth electromagnetic loss three-dimensional superstructure and a sixth hollow column connected to the fifth hollow column through a plurality of connecting blocks; the fifth resistive frequency selective surface is mounted on the top side of the fifth hollow column and the sixth hollow column, and the fifth hollow column is connected to the fourth electromagnetic loss three-dimensional superstructure through the fifth resistive frequency selective surface, wherein the fifth resistive frequency selective surface is a grid-nested square annular uniform sheet resistance film.

[0013] In one embodiment of the present invention, the sixth electromagnetic loss three-dimensional superstructure includes a columnar structure connected to the fifth electromagnetic loss three-dimensional superstructure and a metal backplate, and a mesa structure located within the columnar structure. The inner side of the columnar structure is provided with a vertical metal patch array. The sixth resistive frequency selective surface is mounted on the top side of the columnar structure and is a plurality of right-angled strip uniform sheet resistance films. The seventh resistive frequency selective surface is mounted on the surface of the mesa structure and is a square uniform sheet resistance film.

[0014] As described above, the full-band three-dimensional absorbing metamaterial of the present invention has the following beneficial effects:

[0015] 1. The full-band three-dimensional absorbing metamaterial of the present invention achieves full-band absorption performance in the currently widely used L, S, C, X, Ku, K and Ka bands, and still exhibits effective electromagnetic loss performance in the V and W bands, possessing ultra-wideband absorption characteristics;

[0016] 2. The full-band three-dimensional absorbing metamaterial of this invention has a reflection coefficient of less than -5dB at 1GHz and a frequency point with a reflection coefficient of less than -10dB not exceeding 1.5GHz. While exhibiting ultra-wideband absorption, it also has obvious low-frequency strong absorption performance.

[0017] 3. The full-band three-dimensional absorbing metamaterial of this invention has a relative thickness of less than 0.15λL and an overall thickness that is much less than one-quarter of the starting frequency point where the reflection coefficient is below -10dB, thus possessing a relatively thin thickness.

[0018] 4. The full-band three-dimensional absorbing metamaterial of this invention has low-frequency absorption performance that does not depend on ferrite or metallic magnetic powder, and can significantly reduce surface density.

[0019] 5. The full-band three-dimensional absorbing metamaterial of this invention has the following properties within the 1~50GHz range: under TE polarization, the oblique incident angle for absorption performance with an absorption rate greater than 90% is 45°, and the oblique incident angle for absorption performance with an absorption rate greater than 80% is 60°; under TM polarization, the oblique incident angle for absorption performance with an absorption rate greater than 90% is 70°, and the oblique incident angle for absorption performance with an absorption rate greater than 80% is 75°. Moreover, at an oblique incident angle of 75°, the absorption rate is only between 80% and 90% in the 6.2~14.5GHz range, while the absorption rate in other frequency bands is greater than 90%, demonstrating large oblique incident angle performance.

[0020] In summary, this invention achieves multi-dimensional coupling absorption design by combining resistive frequency surfaces, pure metal patches, and a three-dimensional electromagnetic loss superstructure. This not only enables full-band absorption performance in the currently widely used L, S, C, X, Ku, K, and Ka bands, but also exhibits certain electromagnetic loss performance in the V and W bands. The overall thickness is much less than one-quarter of that at the frequency point where the reflection coefficient is below -10dB, demonstrating a relatively thin profile. The maximum oblique incidence angle is not less than 70°, meeting the current demand for thin-layer, low-area-density electromagnetic absorbing materials operating across the entire frequency range. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the full-band three-dimensional absorbing metamaterial disclosed in the embodiments of the present invention;

[0022] Figure 2 This is a schematic diagram of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in the embodiments of the present invention;

[0023] Figure 3 This is a schematic diagram of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in this embodiment of the invention, from the metal backplate to the first electromagnetic loss three-dimensional metastructure, showing the structure of each layer and the selection of the surface position of the applied resistive frequency.

[0024] Figure 4This is a schematic diagram of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in this embodiment of the invention, from the first electromagnetic loss three-dimensional metastructure to the metal backplate, and the selection of the surface position of the applied resistive frequency.

[0025] Figure 5 This is a schematic diagram of the shape and loading position of the frequency selection surface of each layer of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in the embodiments of the present invention;

[0026] Figure 6 This is a top view of the sixth electromagnetic loss three-dimensional superstructure of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in this embodiment of the invention, and the resistive frequency-selective surface loaded on it.

[0027] Figure 7 This is a left front view schematic diagram of the sixth electromagnetic loss three-dimensional superstructure of the basic structural unit in the full-band three-dimensional absorbing metamaterial disclosed in the embodiments of the present invention, and the resistive frequency selective surface loaded on it.

[0028] Figure 8 This is a graph showing the reflection coefficient of the metasurface loaded in the full-band three-dimensional absorbing metamaterial disclosed in this embodiment of the invention when electromagnetic waves are incident perpendicularly.

[0029] Figure 9 The above are performance diagrams of the full-band three-dimensional absorbing metamaterial disclosed in this invention under TE polarization in the 0~50GHz frequency band at different oblique incident angles.

[0030] Figure 10 The image shows the performance of the full-band three-dimensional absorbing metamaterial disclosed in this invention in the 0~50GHz frequency band under TM polarization at different oblique incidence angles.

[0031] Component designation explanation

[0032] 1. Basic structural unit; 11. First electromagnetic loss three-dimensional superstructure; 111. Top plate; 112. First hollow column; 12. Second electromagnetic loss three-dimensional superstructure; 121. Second hollow column; 122. First support member; 13. Third electromagnetic loss three-dimensional superstructure; 131. Third hollow column; 132. Second support member; 14. Fourth electromagnetic loss three-dimensional superstructure; 141. Fourth hollow column; 142. Third support member; 15. Fifth electromagnetic loss three-dimensional superstructure; 151. Fifth hollow column; 152. Connecting block; 153. Sixth hollow column; 16. Sixth electromagnetic loss three-dimensional superstructure; 161. Columnar structure; 162. Vertical metal patch array; 163. Mesa structure; 17. Metal backplate; 21. First resistive frequency selection surface; 22. Second resistive frequency selection surface; 23. Third resistive frequency selection surface; 24. Fourth resistive frequency selection surface; 25. Fifth resistive frequency selection surface; 251. Grid structure unit; 252. Square ring unit; 26. Sixth resistive frequency selection surface; 27. Seventh resistive frequency selection surface. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0034] Please see Figures 1 to 7 This invention provides a full-band three-dimensional absorbing metamaterial, comprising several basic structural units 1 arranged in a periodic array. The full-band three-dimensional absorbing metamaterial is a two-dimensional periodic arrangement structure, and the basic structural units 1 can be periodically arranged and shaped according to specific needs. The period size is 15.0~40.0mm. In this embodiment, the full-band three-dimensional absorbing metamaterial is arranged in a 4×4 pattern. In practical applications, electromagnetic simulation software CST2025 is used for simulation verification. Floquet ports are used, and the simulation of an infinitely large plane is achieved through a Unit cell.

[0035] exist Figure 2In this structure, the basic structural unit 1 includes, from top to bottom, a first electromagnetic loss three-dimensional superstructure 11, a second electromagnetic loss three-dimensional superstructure 12, a third electromagnetic loss three-dimensional superstructure 13, a fourth electromagnetic loss three-dimensional superstructure 14, a fifth electromagnetic loss three-dimensional superstructure 15, a sixth electromagnetic loss three-dimensional superstructure 16, and a metal backplate 17. The materials used for the first electromagnetic loss three-dimensional superstructure 11 to the sixth electromagnetic loss three-dimensional superstructure 16 are all suitable for 3D printing or flatbed engraving processes and possess certain magnetic or dielectric loss characteristics. It should be noted that these materials include PLA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, and PPS doped with magnetic metal micropowder, etc. The relative permittivity of these materials ranges from 1.5 to 15.0, and the relative permeability ranges from 1.0 to 15.0. The first electromagnetic loss three-dimensional superstructure 11 to the sixth electromagnetic loss three-dimensional superstructure 16 are all prepared using 3D printing or engraving processes.

[0036] Please see Figures 3 to 5 The first electromagnetic loss three-dimensional superstructure 11 is provided with a first resistive frequency selection surface 21. The first electromagnetic loss three-dimensional superstructure 11 includes a top plate 111 and a first hollow column 112 installed on the bottom side of the top plate 111. The bottom side of the first hollow column 112 is connected to the second electromagnetic loss three-dimensional superstructure 12. The first resistive frequency selection surface 21 is located inside the first hollow column 112 and connected to the top plate 111. The first resistive frequency selection surface 21 is a square uniform sheet resistance film. It should be noted that the thickness of the top plate 111 is 0.1~2.0mm, the height of the first hollow column 112 is 0.5~8.0mm, the wall thickness of the first hollow column 112 is 1.0~6.0mm, and the square resistance of the square uniform sheet resistance film ranges from 50~4000Ω / □. In specific description, it can also be said that the first electromagnetic loss three-dimensional superstructure 11 is a planar periodically arranged hollow column structure covered by a flat plate material.

[0037] Please see Figures 3 to 5 The second electromagnetic loss three-dimensional superstructure 12 is provided with a second resistive frequency selection surface 22. The second electromagnetic loss three-dimensional superstructure 12 includes a second hollow column 121 connected to the third electromagnetic loss three-dimensional superstructure 13 and a first support member 122 installed in the top side of the second hollow column 121. The top side of the first support member 122 is connected to the first electromagnetic loss three-dimensional superstructure 11. The second resistive frequency selection surface 22 is installed on the side of the first support member 122 away from the first electromagnetic loss three-dimensional superstructure 11, and the second resistive frequency selection surface 22 is also a square uniform sheet resistance film.

[0038] It should be noted that the height of the second hollow column 121 is 0.5~8.0mm, the wall thickness of the second hollow column 121 is 1.0~6.0mm, and the square uniform sheet resistance film has a square resistance range of 50~4000Ω / □. In practical applications, the second resistive frequency selection surface 22 may also include a substrate, and the square uniform sheet resistance film is disposed on the substrate. Therefore, the second electromagnetic loss three-dimensional superstructure 12 may also be a planar periodically arranged hollow column structure covered by the substrate material of the second resistive frequency selection surface 22, wherein the thickness of the substrate material of the second resistive frequency selection surface 22 is 0.1~2.0mm.

[0039] Please see Figures 3 to 5 The third electromagnetic loss three-dimensional superstructure 13 is provided with a third resistive frequency selection surface 23. The third electromagnetic loss three-dimensional superstructure 13 includes a third hollow column 131 connected to the fourth electromagnetic loss three-dimensional superstructure 14 and a second support member 132 installed in the top side of the third hollow column 131. The third resistive frequency selection surface 23 is installed on the top side of the third hollow column 131 and the second support member 132, and the third hollow column 131 is connected to the second electromagnetic loss three-dimensional superstructure 12 through the third resistive frequency selection surface 23. The third resistive frequency selection surface 23 is a grid-shaped uniform sheet resistance film.

[0040] It should be noted that the height of the third hollow column 131 is 0.5-8.0 mm, the wall thickness of the third hollow column 131 is 1.0-6.0 mm, and the square resistance of the grid-shaped uniform sheet resistance film ranges from 50 to 4000 Ω / □. In practical applications, the third resistive frequency selection surface 23 may also include a substrate, and the grid-shaped uniform sheet resistance film is disposed on the substrate. Therefore, the third electromagnetic loss three-dimensional superstructure 13 may also be a planar periodically arranged hollow column structure covered by the substrate material of the third resistive frequency selection surface 23, wherein the thickness of the substrate material of the third resistive frequency selection surface 23 is 0.1-2.0 mm.

[0041] Please see Figures 3 to 5 The fourth electromagnetic loss three-dimensional superstructure 14 is provided with a fourth resistive frequency selection surface 24. The fourth electromagnetic loss three-dimensional superstructure 14 includes a fourth hollow column 141 connected to the fifth electromagnetic loss three-dimensional superstructure 15 and a third support member 142 installed in the top side of the fourth hollow column 141. The fourth resistive frequency selection surface 24 is installed on the top side of the fourth hollow column 141 and the third support member 142, and the fourth hollow column 141 is connected to the third electromagnetic loss three-dimensional superstructure 13 through the fourth resistive frequency selection surface 24. The fourth resistive frequency selection surface 24 is a square annular uniform sheet resistance film.

[0042] It should be noted that the height of the fourth hollow column 141 is 0.5~8.0mm, the wall thickness of the fourth hollow column 141 is 1.0~6.0mm, and the square resistance of the square annular uniform sheet resistance film ranges from 50~4000Ω / □. In practical applications, the fourth resistive frequency selection surface 24 may also include a substrate, and the square annular uniform sheet resistance film is disposed on the substrate. Therefore, the fourth electromagnetic loss three-dimensional superstructure 14 may also be a planar periodically arranged hollow column structure covered by the substrate material of the fourth resistive frequency selection surface 24, wherein the thickness of the substrate material of the fourth resistive frequency selection surface 24 is 0.1~2.0mm.

[0043] Please see Figures 3 to 5 The fifth electromagnetic loss three-dimensional superstructure 15 is provided with a fifth resistive frequency selection surface 25. The fifth electromagnetic loss three-dimensional superstructure 15 includes a fifth hollow column 151 connected to the sixth electromagnetic loss three-dimensional superstructure 16 and a sixth hollow column 153 connected to the fifth hollow column 151 through a plurality of connecting blocks 152. The fifth resistive frequency selection surface 25 is installed on the top side of the fifth hollow column 151 and the sixth hollow column 153, and the fifth hollow column 151 is connected to the fourth electromagnetic loss three-dimensional superstructure 14 through the fifth resistive frequency selection surface 25. The fifth resistive frequency selection surface 25 is a grid-nested square annular uniform square resistive film.

[0044] It should be noted that the height of the fifth hollow column 151 is 0.5~8.0mm, the wall thickness of the fifth hollow column 151 is 1.0~6.0mm, and the fifth resistive frequency selection surface 25 includes a grid structure unit 251 and a square ring unit 252. The sheet resistance of the grid and the square ring is in the range of 50~4000Ω / □. In practical applications, the fifth resistive frequency selection surface 25 may also include a substrate. The grid-nested square ring uniform sheet resistance film is disposed on the substrate. Therefore, the fifth electromagnetic loss three-dimensional superstructure 15 may also be a planar periodically arranged hollow column structure covered by the substrate material of the fifth electromagnetic loss three-dimensional superstructure 15, wherein the thickness of the substrate material of the fifth electromagnetic loss three-dimensional superstructure 15 is 0.1~2.0mm.

[0045] Please see Figures 3 to 7The sixth electromagnetic loss three-dimensional superstructure 16 is provided with a sixth resistive frequency selection surface 26 and a seventh resistive frequency selection surface 27. The sixth electromagnetic loss three-dimensional superstructure 16 includes a columnar structure 161 connected to the fifth electromagnetic loss three-dimensional superstructure 15 and the metal back plate 17 respectively, and a mesa structure 163 located inside the columnar structure 161. A vertical metal patch array 162 is provided on the inner side of the columnar structure 161. The sixth resistive frequency selection surface 26 is installed on the top side of the columnar structure 161. The sixth resistive frequency selection surface 26 is a plurality of right-angled strip uniform sheet resistance films. The seventh resistive frequency selection surface 27 is installed on the surface of the mesa structure 163. The seventh resistive frequency selection surface 27 is a square uniform sheet resistance film.

[0046] It should be noted that the height of the columnar structure 161 is 1.0~25.0mm, and the wall thickness of the columnar structure 161 is 1.0~6.0mm; the shape of the vertical metal patch array 162 is a convex geometric unit, and the metal unit of the vertical metal patch array 162 and the metal back plate 17 are made of one of gold, silver, or copper metals with an electrical conductivity of 5.8*107S / m. They are prepared and attached to the sixth electromagnetic loss three-dimensional superstructure 16 by methods such as inkjet printing, magnetron sputtering, and bonding; the square resistance of the right-angled strip uniform sheet resistance film ranges from 50 to 4000Ω / □; the square resistance of the square uniform sheet resistance film ranges from 50 to 4000Ω / □; and the first resistive frequency selection surface 21 to the seventh resistive frequency selection surface 27 can be based on the uniform sheet resistance film or on the lumped resistance loaded metal frequency selection surface.

[0047] Specifically, the design principles of this invention are as follows: 1. The full-band absorption performance is mainly achieved through the synergistic absorption effect of the three-dimensional superstructure and the two-dimensional resistive frequency selective surface; 2. The first electromagnetic loss three-dimensional superstructure 11 and the first resistive frequency selective surface 21 loaded on it, the second electromagnetic loss three-dimensional superstructure 12 and the second resistive frequency selective surface 22 loaded on it are the main functional layers that determine the absorption performance in the frequency band near 30GHz; 3. The third electromagnetic loss three-dimensional superstructure 13 and the third resistive frequency selective surface 23 loaded on it, the fourth electromagnetic loss three-dimensional superstructure and the fourth resistive frequency selective surface 24 loaded on it are the main functional layers that determine the absorption performance in the 2~30GHz frequency band; 4. The fifth resistive frequency selective surface 25 loaded on the fifth electromagnetic loss three-dimensional superstructure 15 and the sixth electromagnetic loss three-dimensional superstructure 16 are the main functional layers that determine the low-frequency absorption performance.

[0048] 5. The hollow structure design of the first electromagnetic loss three-dimensional superstructure 11 to the fifth electromagnetic loss three-dimensional superstructure 15 is mainly used to adjust the overall equivalent dielectric constant of the full-band three-dimensional absorbing supermaterial, so that the incident electromagnetic wave can achieve ideal impedance matching in the full-band range, and achieve the purpose of electromagnetic loss in the absorption band above 30GHz; 6. A columnar design facing the metal reflector is added to the fifth electromagnetic loss three-dimensional superstructure 15. The sixth electromagnetic loss three-dimensional superstructure 16 adopts a solid design and is loaded with the sixth resistive frequency selection surface 26 and the seventh resistive frequency selection surface 27, mainly used to increase the equivalent dielectric constant of the bottom layer, so as to reduce the thickness of the full-band three-dimensional absorbing supermaterial; 7. A vertical metal patch array 162 is loaded on the inner surface of the columnar structure in the sixth electromagnetic loss three-dimensional superstructure 16, which can realize impedance adjustment in the oblique incidence state, so as to increase the oblique incidence angle.

[0049] Furthermore, Figure 8 The graphs show the reflection coefficient curves of the metasurface loaded in the embodiments of the present invention when electromagnetic waves are incident perpendicularly. (a) is 1~50GHz, and (b) is 50GHz~100GHz. The frequency bands with reflection coefficients below -10dB in the embodiments are 1.5~57.0GHz and 66.7~97.2GHz. It achieves full-band absorption performance in the L, S, C, X, Ku, K, and Ka bands, and still exhibits effective electromagnetic loss performance in the V and W bands, thus possessing ultra-wideband absorption characteristics.

[0050] Figure 9 This is an embodiment of the present invention, in the 0~50GHz frequency band, under TE polarization, the performance at different oblique incidence angles, (a) is the reflection coefficient, (b) is the absorptivity; when incident vertically, the absorption frequency band with a reflection coefficient below -10dB (corresponding to an absorptivity of 90%) is 1.5~50.0GHz, the oblique incidence angle with an absorptivity greater than 90% is 45°, and the oblique incidence angle with an absorptivity greater than 80% is 60°;

[0051] Figure 10 This is an embodiment of the present invention. In the 0~50GHz frequency band, under TM polarization, the performance at different oblique incidence angles is shown. (a) is the reflection coefficient, and (b) is the absorptivity. When the incidence is perpendicular, the absorption frequency band with a reflection coefficient below -10dB (corresponding to an absorptivity of 90%) is 1.5~50.0GHz. The oblique incidence angle with an absorptivity greater than 90% is 70°, and the oblique incidence angle with an absorptivity greater than 80% is 75°. Moreover, at an oblique incidence angle of 75°, the absorptivity is only between 80% and 90% in the range of 6.2~14.5GHz, while the absorptivity in other frequency bands is greater than 90%, demonstrating performance at large oblique incidence angles.

[0052] In summary, the full-band three-dimensional absorbing metamaterial of this invention achieves full-band absorption performance with a relative thickness of less than 0.15λL through the synergistic absorption effect of the three-dimensional metastructure and the two-dimensional resistive frequency-selective surface. This is achieved through layered absorption design for different frequency bands, impedance matching optimization of the hollow structure design, local equivalent dielectric constant design, and loading of a vertical metal patch array. Furthermore, it possesses excellent oblique incidence stability, making it extremely valuable for improving the performance of electronic devices and effectively reducing the impact of electromagnetic pollution on human health and the environment.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A three-dimensional microwave absorbing metamaterial covering the entire frequency band, characterized in that: It includes several basic structural units (1) arranged in a periodic array. The basic structural unit (1) includes a first electromagnetic loss three-dimensional superstructure (11), a second electromagnetic loss three-dimensional superstructure (12), a third electromagnetic loss three-dimensional superstructure (13), a fourth electromagnetic loss three-dimensional superstructure (14), a fifth electromagnetic loss three-dimensional superstructure (15), a sixth electromagnetic loss three-dimensional superstructure (16) and a metal backplate (17) arranged from top to bottom. The first electromagnetic loss three-dimensional superstructure (11) is provided with a first resistive frequency selection surface (21), the second electromagnetic loss three-dimensional superstructure (12) is provided with a second resistive frequency selection surface (22), the third electromagnetic loss three-dimensional superstructure (13) is provided with a third resistive frequency selection surface (23), the fourth electromagnetic loss three-dimensional superstructure (14) is provided with a fourth resistive frequency selection surface (24), the fifth electromagnetic loss three-dimensional superstructure (15) is provided with a fifth resistive frequency selection surface (25), and the sixth electromagnetic loss three-dimensional superstructure (16) is provided with a sixth resistive frequency selection surface (26) and a seventh resistive frequency selection surface (27). The sixth electromagnetic loss three-dimensional superstructure (16) includes a columnar structure (161) connected to the fifth electromagnetic loss three-dimensional superstructure (15) and the metal backplate (17) respectively, and a mesa structure (163) located in the columnar structure (161). The inner side of the columnar structure (161) is provided with a vertical metal patch array (162). The sixth resistive frequency selection surface (26) is installed on the top side of the columnar structure (161). The sixth resistive frequency selection surface (26) is a plurality of right-angled strip uniform sheet resistance films. The seventh resistive frequency selection surface (27) is installed on the surface of the mesa structure (163). The seventh resistive frequency selection surface (27) is a square uniform sheet resistance film.

2. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The materials used in the first electromagnetic loss three-dimensional superstructure (11), the second electromagnetic loss three-dimensional superstructure (12), the third electromagnetic loss three-dimensional superstructure (13), the fourth electromagnetic loss three-dimensional superstructure (14), the fifth electromagnetic loss three-dimensional superstructure (15) and the sixth electromagnetic loss three-dimensional superstructure (16) are all materials that can be used in 3D printing or flatbed engraving processes and have certain magnetic loss or dielectric loss characteristics.

3. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The first electromagnetic loss three-dimensional superstructure (11) includes a top plate (111) and a first hollow column (112) installed on the bottom side of the top plate (111), and the bottom side of the first hollow column is connected to the second electromagnetic loss three-dimensional superstructure (12). The first resistive frequency selection surface (21) is located inside the first hollow column (112) and connected to the top plate (111), and the first resistive frequency selection surface (21) is a square uniform sheet resistance film.

4. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The second electromagnetic loss three-dimensional superstructure (12) includes a second hollow column (121) connected to the third electromagnetic loss three-dimensional superstructure (13) and a first support member (122) installed in the top side of the second hollow column (121), the top side of the first support member (122) being connected to the first electromagnetic loss three-dimensional superstructure (11). The second resistive frequency selection surface (22) is mounted on the side of the first support (122) away from the first electromagnetic loss three-dimensional superstructure (11), and the second resistive frequency selection surface (22) is also a square uniform sheet resistance film.

5. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The third electromagnetic loss three-dimensional superstructure (13) includes a third hollow column (131) connected to the fourth electromagnetic loss three-dimensional superstructure (14) and a second support member (132) installed in the top side of the third hollow column (131); The third resistive frequency selection surface (23) is installed on the top side of the third hollow column (131) and the second support (132), and the third hollow column (131) is connected to the second electromagnetic loss three-dimensional superstructure (12) through the third resistive frequency selection surface (23). The third resistive frequency selection surface (23) is a grid-shaped uniform sheet resistance film.

6. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The fourth electromagnetic loss three-dimensional superstructure (14) includes a fourth hollow column (141) connected to the fifth electromagnetic loss three-dimensional superstructure (15) and a third support member (142) installed in the top side of the fourth hollow column (141); The fourth resistive frequency selection surface (24) is installed on the top side of the fourth hollow column (141) and the third support (142), and the fourth hollow column (141) is connected to the third electromagnetic loss three-dimensional superstructure (13) through the fourth resistive frequency selection surface (24). The fourth resistive frequency selection surface (24) is a square annular uniform sheet resistance film.

7. The full-band three-dimensional absorbing metamaterial according to claim 1, characterized in that: The fifth electromagnetic loss three-dimensional superstructure (15) includes a fifth hollow column (151) connected to the sixth electromagnetic loss three-dimensional superstructure (16) and a sixth hollow column (153) connected to the fifth hollow column (151) through a plurality of connecting blocks (152); The fifth resistive frequency selection surface (25) is mounted on the top side of the fifth hollow column (151) and the sixth hollow column (153), and the fifth hollow column (151) is connected to the fourth electromagnetic loss three-dimensional superstructure (14) through the fifth resistive frequency selection surface (25). The fifth resistive frequency selection surface (25) is a grid-nested square annular uniform sheet resistance film.

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