Thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure

Abstract

The application provides a thin-layer strong-absorption mechanically adjustable three-dimensional wave-absorbing structure, which comprises a bottom plate, a plurality of basic structure units arranged in a periodic array are arranged on the bottom plate, the basic structure unit comprises a hollow frame installed on the bottom plate, a three-dimensional resistive frequency selection substructure arranged on the outer surface of the hollow frame and a nested height-adjustable metal reflection three-dimensional substructure located in the hollow frame and installed on the bottom plate; the application has the following beneficial effects: the application realizes the absorption performance of a reflection coefficient lower than -20 dB in the range of 8-18 GHz through a simple and unique three-dimensional wave-absorbing structure design, and has good oblique incidence stability; further combined with the nested height-adjustable metal reflection three-dimensional substructure, the application realizes the adjustable reflection coefficient in a wide-band range and at any incident angle, thereby meeting the demand for a new type of electromagnetic wave-absorbing material with thin layers, small area density, strong absorption, adjustable wave-absorbing performance, simple structure and good oblique incidence stability.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorption technology, and in particular to a thin-layer, strong-absorbing, mechanically adjustable three-dimensional wave-absorbing structure. Background Technology

[0002] Electromagnetic absorbing technology is an effective solution to the electromagnetic scattering and pollution problems brought about by the rapid development of electronic information technology. In the military field, with the advancement of detection technology, traditional static absorbing technologies such as absorbing materials and structures are no longer sufficient to meet the needs of improving the survivability of weapon systems. In the civilian electromagnetic protection field, due to the trend of lightweighting and miniaturization of electronic products and the continuous expansion of commonly used electromagnetic frequency bands, existing absorbing technologies are also unable to achieve effective adaptation. Furthermore, both military and civilian applications place higher demands on the strong absorption performance of absorbing materials.

[0003] However, existing absorbing materials and structures still face many limitations: on the one hand, to increase dielectric and magnetic loss performance in absorbing materials, it is usually necessary to dop with metal micropowders (to improve conductivity and polarization loss) or introduce magnetic components such as ferrites (to enhance eddy current loss and optimize impedance matching), resulting in a high material density; on the other hand, when absorbing materials are fabricated as layered structures, they often only achieve strong absorption performance with a reflection coefficient below -20dB in a narrow band. Meanwhile, current absorbing structures generally suffer from insufficient absorption intensity (typically only -10dB), complex broadband absorption structure design, and excessive overall thickness. Therefore, developing a novel electromagnetic absorbing material that is thin-layered, has low surface density, strong absorption, adjustable absorption performance, simple structure, and good oblique incidence stability has become an urgent need. 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 thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure to solve the problems of existing absorbing materials and structures, such as high material density, unadjustable absorption performance, insufficient absorption intensity, complex broadband absorption structure design, and excessive overall thickness.

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

[0006] A thin-layer strong-absorbing mechanically adjustable three-dimensional wave-absorbing structure includes a base plate, on which a plurality of basic structural units are arranged in a periodic array. The basic structural units include a hollow frame mounted on the base plate, a three-dimensional resistive frequency selection substructure disposed on the outer surface of the hollow frame, and a nested height-adjustable metal reflective three-dimensional substructure located inside the hollow frame and mounted on the base plate.

[0007] The three-dimensional resistive frequency selection substructure includes several basic geometric units symmetrically distributed on each surface of the hollow frame. Each basic geometric unit includes a concentric square ring and a circular ring located within the square ring. The square ring and the circular ring each include several trapezoidal blocks and arc blocks mounted on the surface of the hollow frame. The center of each arc block is integrally connected to the center of its corresponding trapezoidal block through a connecting block. The center of the side of each trapezoidal block away from the arc block is integrally connected to the center of a trapezoidal block on its adjacent other surface through a connecting block.

[0008] In one embodiment of the present invention, a plurality of the basic structural units are periodically arranged and shaped on the base plate, and the period size of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure is 6.0~10.0mm.

[0009] In one embodiment of the present invention, the hollow frame is made of a material that can be used for 3D printing or a rigid PCB board, the relative permittivity of the hollow frame is in the range of 1.0 to 10.0, and the dielectric loss of the hollow frame is in the range of 0.001 to 0.5.

[0010] In one embodiment of the present invention, each basic geometric unit in the three-dimensional resistive frequency selector structure is made of metal, and the basic geometric units can be prepared on each surface of the hollow frame by inkjet printing, electrochemical etching or magnetron sputtering.

[0011] In one embodiment of the present invention, the side length of the square ring is 5.8~9.8mm, the radius of the circular ring is 0.5~2.0mm, and the line width of both the square ring and the circular ring is 0.1~1.5mm.

[0012] In one embodiment of the present invention, two adjacent trapezoidal blocks are connected by a first lumped resistor, and two adjacent arc-shaped blocks are connected by a second lumped resistor. The resistance value of the first lumped resistor is between 200 and 1000 Ω, and the resistance value of the second lumped resistor is between 10 and 300 Ω. The gap between the lumped resistors is 0.1 to 0.8 mm. The first and second lumped resistors are obtained by screen printing, spraying conductive material, and directly loading chip resistors through PCB manufacturing processes.

[0013] In one embodiment of the present invention, the nested height-adjustable metal reflective three-dimensional substructure includes two or more regular-shaped concentric pillars of different sizes.

[0014] As described above, the thin-layer, strong-absorbing, mechanically adjustable three-dimensional wave-absorbing structure of the present invention has the following beneficial effects:

[0015] 1. The thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure of the present invention has a relative thickness of 0.119λL. When electromagnetic waves are incident perpendicularly, the reflection coefficient is less than -20dB in the range of 8~18GHz, achieving strong absorption performance at a relatively thin thickness.

[0016] 2. The thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in this invention has an oblique incidence angle of not less than 50° when the reflection coefficient is less than -10dB under TE polarization, and an oblique incidence angle of approximately 20° when the reflection coefficient is less than -20dB.

[0017] 3. The thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in this invention has a reflection coefficient of less than -10dB at an oblique incidence angle of more than 50° under TM polarization; a reflection coefficient of less than -20dB at an oblique incidence angle of more than 30°, and at 40° there is still a reflection coefficient of less than -20dB in some frequency bands.

[0018] 4. The thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in this invention can achieve continuous adjustment of the reflection coefficient in the 4~25GHz frequency band, with an adjustable bandwidth of not less than 21GHz; in particular, the continuous adjustable amplitude in the 8~18GHz frequency band is not less than 20dB, and the adjustable amplitude at some frequency points is greater than 30dB.

[0019] In summary, this invention achieves absorption performance with a reflection coefficient below -20dB in the 8~18GHz range through a simple and unique three-dimensional absorbing structure design, and also possesses good oblique incidence stability. Furthermore, by combining a nested, height-adjustable metal reflective three-dimensional substructure, the reflection coefficient can be adjusted over a wide range at any incident angle, meeting the current demand for novel electromagnetic absorbing materials that are thin-layered, have low surface density, strong absorption, adjustable absorption performance, simple structure, and good oblique incidence stability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the basic structural unit in the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the internal nested, height-adjustable metal reflective three-dimensional substructure of the basic structural unit in the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention.

[0023] Figure 4 This is a schematic diagram of the reflection coefficient and absorptivity under TE polarization when the height of the nested height-adjustable metal reflective three-dimensional substructure inside the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in this embodiment of the invention is 0.

[0024] Figure 5 This is a schematic diagram of the reflection coefficient and absorption rate under TM polarization when the height of the nested height-adjustable metal reflective three-dimensional substructure inside the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure in this embodiment of the invention is 0.

[0025] Figure 6 This is a diagram showing the reflection coefficient variation of the outer cuboid column of the nested height-adjustable metal reflective three-dimensional substructure of the thin-layer strong-absorbing mechanically adjustable three-dimensional absorbing structure in the embodiment of the present invention, at a certain height, in the vertical state.

[0026] Figure 7 This is a diagram showing the reflection coefficient variation of the inner cuboid column of the nested height-adjustable metal reflective three-dimensional substructure of the thin-layer strong-absorbing mechanically adjustable three-dimensional absorbing structure in the embodiment of the present invention, in a vertical state at a certain height.

[0027] Figure 8 This is a graph showing the variation of the reflection coefficient of the outer and inner cuboid columns of the nested height-adjustable metal reflective three-dimensional substructure of the thin-layer strong absorption mechanical adjustable three-dimensional absorbing structure in the embodiment of the present invention at different heights in the vertical state.

[0028] Figure 9 This is a graph showing the reflection coefficient of the outer cuboid column of the nested height-adjustable metal reflective three-dimensional substructure of the thin-layer strong-absorbing mechanically adjustable three-dimensional absorbing structure in this embodiment of the invention at different heights and oblique incident angles of 45°.

[0029] Figure 10 This diagram shows the reflection coefficient variation of the inner cuboid column of the nested height-adjustable metal reflective three-dimensional substructure within the thin-layer strong-absorbing mechanically adjustable three-dimensional absorbing structure in this embodiment of the invention at different heights and oblique incident angles of 45°.

[0030] Component designation explanation

[0031] 1. Base plate; 2. Basic structural unit; 21. Hollow frame; 22. Three-dimensional resistive frequency selection substructure; 221. Basic geometric unit; 2211. Square ring; 2212. Circular ring; 23. Nested height-adjustable metal reflective three-dimensional substructure; 231. Outer cuboid column; 232. Inner cuboid column; 3. Trapezoidal block; 4. Arc block; 5. First lumped resistor; 6. Second lumped resistor. Detailed Implementation

[0032] 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.

[0033] Please see Figures 1 to 3 This invention provides a thin-layer, strongly absorbing, mechanically adjustable three-dimensional wave-absorbing structure, including a base plate 1. The base plate 1 has a plurality of basic structural units 2 arranged in a periodic array. This thin-layer, strongly absorbing, mechanically adjustable three-dimensional wave-absorbing structure can periodically arrange and shape the basic structural units 2 according to specific needs. The period of the thin-layer, strongly absorbing, mechanically adjustable three-dimensional wave-absorbing structure is 6.0~10.0 mm. Figure 1 As shown; the basic structural unit 2 includes a hollow frame 21 mounted on a base plate 1, a three-dimensional resistive frequency selection substructure 22 disposed on the outer surface of the hollow frame 21, and a nested height-adjustable metal reflective three-dimensional substructure 23 located inside the hollow frame 21 and mounted on the base plate 1; wherein, the hollow frame 21 is made of a material suitable for 3D printing or a rigid PCB board, the relative permittivity of the hollow frame 21 is in the range of 1.0~10.0, and the dielectric loss of the hollow frame 21 is in the range of 0.001~0.5;

[0034] It should be noted that the hollow frame 21 in this embodiment is a hollow cuboid frame with a side length of 5.9~9.9mm and a thickness of 0.1~1.0mm for each surface. Materials that can be used for 3D printing include PLA, PETG and TPU, and rigid PCB boards include FR4 and F4B. Therefore, the material of the hollow cuboid frame can be PLA, PETG, TPU and other materials that can be used for 3D printing, or it can be FR4, F4B and other rigid PCB boards.

[0035] exist Figure 2 and Figure 3 In this embodiment, the three-dimensional resistive frequency selector substructure 22 includes several basic geometric units 221 symmetrically distributed on each surface of the hollow frame 21. It should be noted that the number of basic geometric units 221 in this embodiment is 5. Furthermore, each basic geometric unit 221 in the three-dimensional resistive frequency selector substructure 22 is made of a metal material, which is one of gold, silver, or copper. The basic geometric units 221 can be prepared on the 5 surfaces of the hollow frame 21 by inkjet printing, electrochemical etching, or magnetron sputtering.

[0036] The basic geometric unit 221 includes concentric square rings 2211 and circular rings 2212 located within the square rings 2211. Alternatively, the basic geometric unit 221 can be described as being formed by concentric circular rings 2212 and square rings 2211 connected in a cross shape. Five basic geometric units 221 are symmetrically distributed on the five surfaces of the hollow cuboid frame. The side length of the square rings 2211 is 5.8~9.8 mm, and the radius of the circular rings 2212 is 0.5~2.0 mm. The line widths of both the square rings 2211 and the circular rings 2212 are... The thickness is 0.1~1.5mm; the square ring 2211 and the circular ring 2212 each include a number of trapezoidal blocks 3 and arc-shaped blocks 4 installed on the surface of the hollow frame 21. The center of each arc-shaped block 4 is integrally connected to the center of its corresponding trapezoidal block 3 through a connecting block. The center of the side of each trapezoidal block 3 away from the arc-shaped block 4 is integrally connected to the center of the trapezoidal block 3 on its adjacent other surface through a connecting block. It should be noted that in this embodiment, the number of trapezoidal blocks 3 and arc-shaped blocks 4 are both 4.

[0037] Two adjacent trapezoidal blocks 3 are connected by a first lumped resistor 5, and two adjacent arc-shaped blocks 4 are connected by a second lumped resistor 6. That is, four first lumped resistors 5 are symmetrically loaded on the square ring 2211, and the resistance value of the first lumped resistor 5 is between 200 and 1000Ω. Four second lumped resistors 6 are symmetrically loaded on the circular ring 2212, and the resistance value of the second lumped resistors is between 10 and 300Ω. The gap between the lumped resistors is 0.1 to 0.8mm. The first lumped resistors 5 and the second lumped resistors 6 can be obtained by screen printing, spraying conductive material, etc., or they can be directly loaded as chip resistors through PCB manufacturing process.

[0038] exist Figure 3 In this embodiment, the nested height-adjustable metal reflective three-dimensional substructure 23 includes two or more concentric regular-shaped pillars of different sizes. Specifically, the nested height-adjustable metal reflective three-dimensional substructure 23 in this embodiment can be composed of two or more concentric cuboid pillars of different sizes. The height of the nested height-adjustable metal reflective three-dimensional substructure 23 is 0~9.7mm. The nested height-adjustable metal reflective three-dimensional substructure 23 in this embodiment includes an outer cuboid pillar 231 installed on the base plate 1 and an inner cuboid pillar 232 installed on the outer cuboid pillar 231. Furthermore, the nested height-adjustable metal reflective three-dimensional substructure 23 can be covered with a metal layer by methods such as inkjet printing, electrochemical etching, magnetron sputtering, or direct bonding on a frame made of materials suitable for 3D printing such as PLA, PETG, and TPU, or a frame made of rigid PCB boards such as FR4 and F4B. In other words, the outer surface of the nested height-adjustable metal reflective three-dimensional substructure 23 is provided with a metal layer.

[0039] Specifically, the design principles of this invention are as follows: 1. The three-dimensional resistive frequency selective substructure 22 is the main source of electromagnetic loss in this invention. By interconnecting the resistive frequency selective surfaces on the five faces of the hollow cuboid frame, the horizontal and vertical spaces are fully utilized to achieve miniaturization of the spatial units and realize broadband absorption performance; 2. In this three-dimensional absorbing structure, multiple spatial capacitors are formed between two adjacent basic structural units 2 and between the mirror-symmetric metal units on the vertical surface, achieving good impedance matching effect in the broadband range and realizing strong absorption performance with a reflection coefficient of less than -20dB;

[0040] 3. Each structural unit of the three-dimensional absorbing structure achieves large-angle oblique incidence performance by loading resistive frequency-selective surface units on the side. 4. The design of the hollow cuboid frame improves the impedance matching effect of the structure itself, which is the basis for realizing broadband absorption design. 5. By adding nested height-adjustable metal reflective three-dimensional substructures 23 inside the hollow cuboid frame, and combining and adjusting the height of the nested height-adjustable metal reflective three-dimensional substructures 23, the reflected electromagnetic waves and resonant loss conditions in space are reconstructed, and the gradient of the absorbing type is adjustable.

[0041] Furthermore, Figure 4 The thin-layer, strong-absorbing, mechanically adjustable three-dimensional absorbing structure of this invention, with its internal nested, height-adjustable metal reflective three-dimensional substructure 23 having a height of 0, exhibits the following reflection coefficients and absorptivity under TE polarization: At perpendicular incidence, the absorption frequency band with a reflection coefficient below -10dB (corresponding to an absorptivity of 90%) is 6.5~19.0GHz; at an oblique incidence angle of 50°, the absorption frequency band with a reflection coefficient below -10dB is 7.5~20.4GHz; and at an incidence angle of 60°, the absorptivity is still greater than 80% in the 7.3~23.4GHz range. At perpendicular incidence, the frequency band with a reflection coefficient below -20dB (corresponding to an absorptivity of 99%) is 7.7~18.0GHz; the maximum oblique incidence angle for the frequency band with a reflection coefficient below -20dB is between 10-20°.

[0042] Figure 5The thin-layer, strong-absorbing, mechanically adjustable three-dimensional absorbing structure of this invention, with its internal nested, height-adjustable metal reflective three-dimensional substructure 23 having a height of 0, exhibits the following reflection coefficient and absorptivity under TM polarization: At perpendicular incidence, the absorption frequency band with a reflection coefficient below -10dB (corresponding to an absorptivity of 90%) is 6.5~19.0GHz; at an oblique incidence angle of 50°, the absorption frequency band with a reflection coefficient below -10dB is 7.6~20.4GHz; and at an incidence angle of 60°, the absorptivity is still greater than 80% in the 6.9~18.6GHz range. At perpendicular incidence, the frequency band with a reflection coefficient below -20dB (corresponding to an absorptivity of 99%) is 7.7~18.0GHz; the maximum oblique incidence angle for the frequency band with a reflection coefficient below -20dB is not less than 30°.

[0043] Figure 6 This is a schematic diagram showing the reflection coefficient change of the outer cuboid column 231 of the internally nested height-adjustable metal reflective three-dimensional absorbing structure 23 in a vertical state at a certain height, according to an embodiment of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention. The embodiment, by adjusting only the height of the outer cuboid column 231 of the internally nested height-adjustable metal reflective three-dimensional substructure 23, can achieve continuously adjustable reflection coefficients from strong reflection to strong absorption in the 4~25GHz frequency band, with an adjustable bandwidth of not less than 21GHz; specifically, the continuously adjustable amplitude in the 8~18GHz frequency band is not less than 20dB.

[0044] Figure 7 This is a schematic diagram showing the change in reflection coefficient of the inner cuboid column 232 of the internally nested height-adjustable metal reflective three-dimensional absorbing structure 23 in a vertical state at a certain height in an embodiment of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention; the embodiment can achieve continuously adjustable reflection coefficient from weak absorption to strong absorption in the 7~19GHz frequency band when only the height of the inner cuboid column 232 of the internally nested height-adjustable metal reflective three-dimensional substructure 23 is adjusted, with an adjustable bandwidth of not less than 12GHz, and the maximum adjustable amplitude at some frequency points can reach 20dB;

[0045] Figure 8 This is a schematic diagram showing the change in reflection coefficient of the outer and inner cuboid columns of the internally nested height-adjustable metal reflective three-dimensional absorbing structure 23 at different heights in the vertical state, in an embodiment of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention. The embodiment can increase the number of continuously adjustable states of reflection coefficient from strong reflection to strong absorption in the 4~25GHz frequency band when the height of the outer cuboid column 231 of the internally nested height-adjustable metal reflective three-dimensional substructure 23 is adjusted simultaneously.

[0046] Figure 9This is a schematic diagram showing the reflection coefficient change of the outer cuboid column 231 of the internally nested height-adjustable metal reflective three-dimensional absorbing structure 23 at different heights and with an oblique incidence angle of 45° in an embodiment of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention. It can be seen that when only the height of the outer cuboid column 231 of the externally nested height-adjustable metal reflective three-dimensional substructure 23 is adjusted, the embodiment can still achieve continuously adjustable performance of the reflection coefficient from strong reflection to strong absorption in the 4~25GHz frequency band, with an adjustable bandwidth of not less than 21GHz; the maximum adjustable amplitude at some frequency points can reach 25dB.

[0047] Figure 10 This is a schematic diagram showing the reflection coefficient change of the inner cuboid column 232 of the internally nested height-adjustable metal reflective three-dimensional substructure 23 at different heights and with an oblique incidence angle of 45° in an embodiment of the thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure of the present invention. It can be seen that when only the height of the outer cuboid column 231 of the internally nested height-adjustable metal reflective three-dimensional substructure 23 is adjusted, the embodiment can achieve continuously adjustable performance of the reflection coefficient from weak absorption to strong absorption in the 7~20GHz frequency band, with an adjustable bandwidth of not less than 13GHz. Through mechanical adjustment, strong absorption performance at some frequency points can be achieved, and the minimum reflection coefficient can reach -54.5dB.

[0048] In summary, this invention, through the interconnection design of the resistive frequency selective surfaces in the three-dimensional resistive frequency selective substructure 22, fully utilizes horizontal and vertical space to achieve miniaturization of spatial units, constructs multiple spatial capacitances between adjacent structural units, and constructs a multi-dimensional loss design. The invention utilizes a hollow cuboid frame design to improve the impedance matching effect of the structure itself, creates conditions for reflected electromagnetic waves and resonant losses within the reconstruction space, and ultimately achieves broadband, strong absorption, large oblique incidence angles under two polarizations, and continuously adjustable absorption performance. Furthermore, through its simple design, this invention meets the current demand for novel electromagnetic absorbing materials that are thin-layered, have low surface density, strong absorption, adjustable absorption performance, simple structure, and good oblique incidence stability, thus possessing significant application value.

[0049] 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 thin-layer, strong-absorbing, mechanically adjustable three-dimensional wave-absorbing structure, comprising a base plate (1), characterized in that: The base plate (1) is provided with a number of basic structural units (2) arranged in a periodic array. The basic structural unit (2) includes a hollow frame (21) installed on the base plate (1), a three-dimensional resistive frequency selection substructure (22) disposed on the outer surface of the hollow frame (21), and a nested height-adjustable metal reflective three-dimensional substructure (23) located inside the hollow frame (21) and installed on the base plate (1). The three-dimensional resistive frequency selection substructure (22) includes several basic geometric units (221) symmetrically distributed on each surface of the hollow frame (21). The basic geometric unit (221) includes a concentric square ring (2211) and a circular ring (2212) located within the square ring (2211). The square ring (2211) and the circular ring (2212) each include several trapezoidal blocks (3) and arc blocks (4) installed on the surface of the hollow frame (21). The center of each arc block (4) is integrally connected to the center of its corresponding trapezoidal block (3) through a connecting block. The center of the side of each trapezoidal block (3) away from the arc block (4) is integrally connected to the center of the trapezoidal block (3) on its adjacent other surface through a connecting block. The nested height-adjustable metal reflective three-dimensional substructure (23) includes two or more regular-shaped concentric cylinders of different sizes.

2. The thin-layer strong absorption mechanically adjustable three-dimensional absorbing structure according to claim 1, characterized in that: Several basic structural units (2) are periodically arranged and shaped on the base plate (1), and the period size of the thin-layer strong absorption mechanically adjustable three-dimensional wave absorbing structure is 6.0~10.0mm.

3. The thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure according to claim 1, characterized in that: The hollow frame (21) is made of a material that can be used for 3D printing or a rigid PCB board. The relative permittivity of the hollow frame (21) is in the range of 1.0 to 10.0, and the dielectric loss of the hollow frame (21) is in the range of 0.001 to 0.

5.

4. The thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure according to claim 1, characterized in that: The basic geometric units (221) in the three-dimensional resistive frequency selector substructure (22) are made of metal. The basic geometric units (221) can be prepared on the surface of the hollow frame (21) by inkjet printing, electrochemical etching or magnetron sputtering.

5. The thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure according to claim 1, characterized in that: The square ring (2211) has a side length of 5.8~9.8mm, the circular ring (2212) has a radius of 0.5~2.0mm, and the line width of both the square ring (2211) and the circular ring (2212) is 0.1~1.5mm.

6. The thin-layer strong absorption mechanically adjustable three-dimensional wave-absorbing structure according to claim 1, characterized in that: Two adjacent trapezoidal blocks (3) are connected by a first lumped resistor (5), and two adjacent arc-shaped blocks (4) are connected by a second lumped resistor (6). The resistance of the first lumped resistor (5) is between 200 and 1000 Ω, and the resistance of the second lumped resistor (6) is between 10 and 300 Ω. The gap between the lumped resistors is 0.1 to 0.8 mm. The first lumped resistor (5) and the second lumped resistor (6) can be obtained by screen printing, spraying conductive material, or directly loading chip resistors through PCB manufacturing process.

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