A double-layer resonant coupling wave absorber

Abstract

The application discloses a double-layer resonant coupling wave-absorbing body, which comprises a metal back plate and a plurality of array-arranged wave-absorbing units placed on the metal back plate, wherein the wave-absorbing unit comprises a first dielectric layer, a first wave-absorbing structure layer, a second dielectric layer, a second wave-absorbing structure and a third dielectric layer which are sequentially stacked, and the first dielectric layer is the bottom layer and is connected with the metal back plate. The application designs an ultra-wide spectrum wave-absorbing material based on double-layer wave-absorbing structure layers and in combination with the sheet resistance of a resistive film, realizes low-frequency, medium-frequency and high-frequency wave-absorbing peaks by reasonably selecting the surface resistance of the resistive film and structure parameters, and enhances the low-frequency absorption intensity, thereby widening the overall wave-absorbing bandwidth and realizing a wave-absorbing performance less than -10 dB in the range of 2-60 GHz. By using the isotropy of the outer circle and inner square and the inner circle and outer square geometric structures, electromagnetic waves with a direction of more than 60 degrees can be realized, and the electromagnetic waves all maintain the ultra-wide and ultra-strong absorption characteristics, thereby realizing an ultra-thin and ultra-wide wave-absorbing body in the range of 2-60 GHz.

Description

Technical Field

[0001] This invention relates to the field of new materials technology, and in particular to a double-layer resonant coupling absorber. Background Technology

[0002] With the rapid development of the 5G communication industry and electronic information technology, the research, development, and production testing of various 5G communication-related basic equipment, such as base stations and antenna arrays, as well as various smart home devices, mobile phones, smart bracelets, Bluetooth headsets, autonomous driving, and other products, all require specific clean electromagnetic environments. These typically include microwave anechoic chambers and radio wave anechoic chambers for research and development, and electromagnetic shielding boxes or small-to-medium-sized shielded anechoic chambers for production line testing. The core of all these testing applications is absorbing materials. Furthermore, with the continuous increase in communication frequency bands, 5G has now reached 26GHz and 39GHz in the millimeter-wave band. Developing novel, controllable, ultra-thin, ultra-wideband absorbing materials is crucial for promoting the research, development, production, and quality control of basic modules in various high-precision fields such as 5G communication, the Internet of Things, and intelligent driving.

[0003] Broadband absorption has always been a major obstacle to breakthroughs and upgrades in microwave absorbing materials. Electromagnetic waves interact with patterns of different shapes to generate multiple absorption peaks, and also interact with patterns of the same shape but different sizes. By reasonably adjusting the shape and size parameters of the pattern, it is possible to make the absorption peaks superimpose to form broadband absorption. Researchers have carried out a great deal of work on the ultrathin, multi-peak, broadband, oblique incidence, and tunable aspects of periodic microwave absorbing structures, and have established various models for analysis. However, each equivalent model is not yet fully applicable to all fields of application. Although periodic microwave absorbing structures have achieved significant results in ultrathin and multi-peak absorption, how to achieve effective broadband absorption while ensuring a relatively thin thickness remains a major challenge for the development of microwave absorbing materials. Due to the lack of an effective equivalent circuit analysis model, broadband absorption remains a bottleneck, especially in the low-frequency broadband absorption range. The gap with foreign countries is mainly reflected in the following three aspects:

[0004] 1) Broadening the low-frequency absorption performance. Domestic scholars mainly focus on designing absorbing materials in the high-frequency C, X, and Ku bands, while only a very few operate in the S or L bands, and the absorption bandwidth is relatively narrow.

[0005] 2) Reduce the thickness of the absorbing material. The absorbing bandwidth and thickness of the absorbing material are contradictory. Broadband absorbing materials are often very thick and heavy, while thin and light absorbing materials can only work in a very narrow frequency band.

[0006] 3) High difficulty in industrial application.

[0007] Currently, structural absorbing materials can be composed of lightweight materials such as foam with added absorbents, and multiple layers can be stacked to achieve broadband absorption, thus possessing the advantages of being lightweight and having a wide bandwidth. However, multi-layered absorbing structures are usually quite thick, have poor low-frequency absorption performance, occupy a large space, and suffer from a decrease in overall mechanical properties due to the multi-layer bonding process; it is difficult to achieve a broadband absorption effect. A typical absorbing screen can be composed of a resistive film loaded on the surface of foam, with a thickness of one-quarter of the wavelength at the center operating frequency. By selecting a resistive film with a suitable sheet resistance value and making it into a frequency-selective surface pattern, its operating frequency band can be adjusted. Commonly used patterns include squares, crosses, and square rings. However, these patterns are limited by their inherent characteristics, having only one absorption peak in the low-frequency band (the band with a thickness less than one-quarter of the wavelength), making it difficult to achieve an ultra-wideband (1.5GHz-80GHz) absorption effect. Therefore, without changing the material and the thickness of the absorbing body, the problem of expanding the absorption bandwidth of the absorbing body across the entire low and high frequency bands has become an urgent technical problem to be solved in the field of electromagnetic wave absorption technology.

[0008] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a double-layer resonant coupled absorber that meets the absorption requirements in a wide frequency range.

[0010] The technical solution of the present invention is as follows: A double-layer resonant coupling absorber is provided, comprising: a metal backplate, and a plurality of absorber units arranged in an array on the metal backplate. Each absorber unit includes a first dielectric layer, a first absorber structure layer, a second dielectric layer, a second absorber structure, and a third dielectric layer stacked sequentially. The first dielectric layer is the bottom layer and is connected to the metal backplate. The thickness of the first, second, and third dielectric layers ranges from 0.8 to 1.5 mm, and the dielectric constant ε ranges from 0.7 to 1.6. The first absorber structure layer includes a first annular resistive pattern, and the second absorber structure layer includes a second annular resistive pattern. The period of both the first and second annular resistive patterns is P, i.e., the distance between the centers of two adjacent first annular resistive patterns and the period of the second annular resistive pattern. The distance between the centers is P, and 10mm≤P≤35mm. The first annular resistor pattern is an inner circle outer square annular structure. The radius of the inner circle is R1, and 3mm≤R1≤10mm. The side length of the outer square is L1, and 4mm≤L1≤12mm. The sheet resistance of the first annular resistor pattern is Rs1, and the range of Rs1 is 50-1000Ω / □. The second annular resistor pattern is an inner square outer circle annular structure. The radius of the outer circle is R2, and 4mm≤R2≤12mm. The side length of the inner square is L2, and 3mm≤L2≤10mm. The sheet resistance of the second annular resistor pattern is Rs2, and the range of Rs2 is 50-1000Ω / □. The points projected onto the metal backplate by the center of the first annular resistor pattern and the center of the second annular resistor pattern in the absorbing unit are distributed within a circle with a diameter of 4mm. The absorber design of this invention is compatible with both square rings, which have good low-frequency absorption, and circular ring resistive films, which have good isotropy. After the dielectric layer is stacked, a coupling-enhanced absorption is formed, and the square ring and the circular ring complement each other, thus achieving a better absorption effect of the multilayer absorber structure.

[0011] Furthermore, the center of the first annular resistor pattern and the center of the second annular resistor pattern in the absorbing unit are projected onto the same point on the metal backplate.

[0012] Furthermore, the first absorbing structure layer further includes a first thin film layer, and the second absorbing structure layer further includes a second thin film layer. The first annular resistor pattern is disposed on the first thin film layer, and the second annular resistor pattern is disposed on the second thin film layer. The thickness of the first thin film layer and the second thin film layer is 0.01mm-0.3mm. Preferably, the first annular resistor pattern and the second annular resistor pattern are obtained by screen printing resistive paste onto the first thin film layer and the second thin film layer, respectively.

[0013] Furthermore, the first and second film layers are polyimide films or PET films.

[0014] Furthermore, the first dielectric layer, the second dielectric layer, and the third dielectric layer are made of honeycomb material panels, lightweight polymethacrylimide foam boards, or polyvinyl chloride foam boards.

[0015] Furthermore, the metal backplate, the first dielectric layer, the first microwave absorbing structure layer, the second dielectric layer, the second microwave absorbing structure, and the third dielectric layer are connected by an adhesive film layer, the adhesive film layer being made of phenolic resin, epoxy resin, or unsaturated polyester resin.

[0016] Furthermore, the adhesive film layer contains a fibrous material, which may be glass fiber, carbon fiber, or organic fiber, to enhance the overall strength.

[0017] Furthermore, the first annular resistor pattern and the second annular resistor pattern are distributed and printed on the first thin film layer and the second thin film layer by screen printing.

[0018] Furthermore, the periods of the first and second annular resistor patterns are both P=20mm. The first annular resistor pattern is an inner circle outer square ring structure with an inner circle radius of R1=7mm and an outer square side length of L1=10mm. The sheet resistance of the first annular resistor pattern is Rs1=600Ω / □. The second annular resistor pattern is an inner square outer circle ring structure with an outer circle radius of R2=10mm and an inner square side length of L2=7mm. The sheet resistance of the second annular resistor pattern is Rs2, and the range of Rs2 is 400Ω / □. The thickness of the first, second, and third dielectric layers is 1.1mm, and the dielectric constant ε is 1.08. In the 2-60GHz range, the reflectivity is less than -10dB when the oblique incidence is less than 60°.

[0019] Furthermore, the periods of the first and second annular resistor patterns are both P=20mm. The first annular resistor pattern is an inner circle outer square ring structure with an inner circle radius of R1=7mm and an outer square side length of L1=10mm. The sheet resistance of the first annular resistor pattern is Rs1=600Ω / □. The second annular resistor pattern is an inner square outer circle ring structure with an outer circle radius of R2=10mm and an inner square side length of L2=7mm. The sheet resistance of the second annular resistor pattern is Rs2, and the range of Rs2 is 400Ω / □. The thickness of the first, second, and third dielectric layers is 1.1mm, and the dielectric constant ε is 1.08. In the 2-60GHz range, the reflectivity under vertical irradiation is less than -10dB.

[0020] Using the above scheme, this invention provides a double-layer resonant coupling absorber. Based on a double-layer absorbing structure, and combined with the sheet resistance of the resistive film, an ultra-wideband absorbing material is designed. By rationally selecting the surface resistance value and structural parameters of the resistive film, absorption peaks at low, mid, and high frequencies are achieved, while enhancing the low-frequency absorption intensity, thereby broadening the overall absorption bandwidth. Absorption performance of less than -10dB can be achieved in the 2-60GHz range. Utilizing the isotropy of the outer circle-inner square and inner circle-outer square geometric structures, ultra-wide and ultra-strong absorption characteristics are maintained for electromagnetic waves with an incoming direction of less than 60 degrees, realizing an ultra-thin and ultra-wide absorber for the 2-60GHz range. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the absorbing unit structure;

[0023] Figure 3 This is a diagram showing the absorption performance of an embodiment of the present invention under direct electromagnetic wave radiation at 90° and under simulated conditions;

[0024] Figure 4 for Figure 3 The absorption performance of the embodiment under electromagnetic waves at different incident angles is shown in the figure. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] Please see Figure 1 and Figure 2This invention provides a dual-layer resonant coupling absorber, comprising: a metal backplate 10, and a plurality of absorber units arranged in an array on the metal backplate 10. Each absorber unit includes a first dielectric layer 20, a first absorber structure layer, a second dielectric layer 30, a second absorber structure, and a third dielectric layer 40 stacked sequentially. The first dielectric layer 20 is the bottom layer and is connected to the metal backplate 10. The thickness of the first dielectric layer 20, the second dielectric layer 30, and the third dielectric layer 40 ranges from 0.8 to 1.5 mm, and the dielectric constant ε ranges from 0.7 to 1.6. The first absorber structure layer includes a first annular resistor pattern 51, and the second absorber structure layer includes a second annular resistor pattern 61. The period of both the first annular resistor pattern 51 and the second annular resistor pattern 61 is P, which is the distance between the centers of two adjacent first annular resistor patterns 51 and the distance between the centers of two adjacent first annular resistor patterns 61. The distance between the centers of the resistor patterns 51 is P, and 10mm≤P≤35mm. The first annular resistor pattern 51 has an inner circle and an outer square ring structure. The radius of the inner circle is R1, and 3mm≤R1≤10mm. The side length of the outer square is L1, and 4mm≤L1≤12mm. The sheet resistance of the first annular resistor pattern 51 is Rs1, and the range of Rs1 is 50-1000Ω / □. The second annular resistor pattern 61 has an inner square and an outer circle ring structure. The radius of the outer circle is R2, and 4mm≤R2≤12mm. The side length of the inner square is L2, and 3mm≤L2≤10mm. The sheet resistance of the second annular resistor pattern 61 is Rs2, and the range of Rs2 is 50-1000Ω / □. The points projected onto the metal backplate 10 by the centers of the first annular resistor pattern 51 and the second annular resistor pattern in the absorbing unit are distributed within a circle with a diameter of 4mm. In this embodiment, the metal backplate 10 is made of aluminum plate.

[0027] The center of the first annular resistor pattern 51 and the center of the second annular resistor pattern in the absorbing unit are projected onto the same point on the metal backplate 10.

[0028] The first absorbing structure layer further includes a first thin film layer 52, and the second absorbing structure layer further includes a second thin film layer 62. The first annular resistor pattern 51 is disposed on the first thin film layer 52, and the second annular resistor pattern 61 is disposed on the second thin film layer 62. The thickness of the first thin film layer 52 and the second thin film layer 62 is 0.01mm-0.3mm.

[0029] The first thin film layer 52 and the second thin film layer 62 are polyimide films.

[0030] The first dielectric layer 20, the second dielectric layer 30, and the third dielectric layer 40 are made of lightweight polymethacrylimide foam board.

[0031] The metal backplate 10, the first dielectric layer 20, the first microwave absorbing structure layer, the second dielectric layer 30, the second microwave absorbing structure, and the third dielectric layer 40 are connected by an adhesive film layer, the adhesive film layer being made of epoxy resin.

[0032] The adhesive film layer contains a fiber material, which is glass fiber.

[0033] The first annular resistor pattern 51 and the second annular resistor pattern 61 are printed on the first thin film layer 52 and the second thin film layer 62 by screen printing.

[0034] Please see Figure 3 and Figure 4 In this embodiment, the period of the first annular resistor pattern 51 and the period of the second annular resistor pattern 61 are both P=20mm. The first annular resistor pattern 51 is an inner circle outer square annular structure with an inner circle radius of R1=7mm and an outer square side length of L1=10mm. The sheet resistance of the first annular resistor pattern 51 is Rs1=600Ω / □. The second annular resistor pattern 61 is an inner square outer circle annular structure with an outer circle radius of R2=10mm and an inner square side length of L2=7mm. The sheet resistance of the second annular resistor pattern 61 is Rs2, and the range of Rs2 is 400Ω / □. The thickness of the first dielectric layer 20, the second dielectric layer 30, and the third dielectric layer 40 is 1.1mm, and the dielectric constant ε is 1.08. In the 2-60GHz range, the reflectivity is less than -10dB when oblique incidence is less than 60°. In the 2-60GHz range, the reflectivity is less than -10dB when vertically irradiated. TE represents actual testing, and TM represents simulation.

[0035] In summary, this invention provides a double-layer resonant coupling absorber. Based on a double-layer absorbing structure and combined with the sheet resistance of a resistive film, an ultra-wideband absorbing material is designed. By rationally selecting the surface resistance value and structural parameters of the resistive film, absorption peaks at low, mid, and high frequencies are achieved, while enhancing the low-frequency absorption intensity, thereby broadening the overall absorption bandwidth. Absorption performance of less than -10dB can be achieved in the 2-60GHz range. Utilizing the isotropy of the outer circle-inner square and inner circle-outer square geometric structures, ultra-wide and ultra-strong absorption characteristics are maintained for electromagnetic waves with an incoming direction of less than 60 degrees, realizing an ultra-thin and ultra-wideband absorber for the 2-60GHz range.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A double-layer resonant coupled absorber, characterized in that, include: A metal backplate, with several arrayed absorbing units placed on the metal backplate. Each absorbing unit comprises a first dielectric layer, a first absorbing structural layer, a second dielectric layer, another second absorbing structural layer, and a third dielectric layer stacked sequentially. The first dielectric layer is the bottom layer and is connected to the metal backplate. The thickness of the first, second, and third dielectric layers ranges from 0.8 to 1.5 mm, and their dielectric constant ε ranges from 0.7 to 1.

6. The first absorbing structural layer includes a first annular resistor pattern, and the second absorbing structural layer includes a second annular resistor pattern. The period of both the first and second annular resistor patterns is P, meaning the distance between the centers of two adjacent first annular resistor patterns is P, and 10 mm ≤ P ≤ 35 mm. The first annular resistor pattern has an inner circle and an outer square annular structure. The radius of the inner circle is R1, and 3 mm ≤ R1 ≤ 10 mm. The side length of the outer square is L1, and 4 mm ≤ L1 ≤ 12 mm. The sheet resistance of the first annular resistor pattern is Rs1, and Rs1 ranges from 50 to 1000 Ω / □. The second annular resistor pattern has an inner square and outer circular structure. The radius of the outer circle is R2, and 4mm ≤ R2 ≤ 12mm. The side length of the inner square is L2, and 3mm ≤ L2 ≤ 10mm. The sheet resistance of the second annular resistor pattern is Rs2, and the range of Rs2 is 50-1000Ω / □. The points projected onto the metal backplate by the center of the first annular resistor pattern and the center of the second annular resistor pattern in the absorbing unit are distributed within a circle with a diameter of 4mm. The periods of the first and second annular resistor patterns are both P = 20mm. The first annular resistor pattern has an inner circular and outer square structure. The radius of the inner circle is R1 = 7mm, and the side length of the outer square is L1 = 10mm. The sheet resistance of the first annular resistor pattern is Rs1 = 600Ω / □. The second annular resistor pattern has an inner square and outer circular structure. The radius of the outer circle is R2 = 10mm, and the side length of the inner square is L2 = 7mm. The sheet resistance of the second annular resistor pattern is Rs2, and Rs2 The range is 400Ω / □; the thickness of the first dielectric layer, the second dielectric layer, and the third dielectric layer is 1.1mm, and the dielectric constant ε is 1.08; in the range of 2-60GHz, the reflectivity is less than -10dB when the oblique incidence is less than 60°, and the reflectivity is less than -10dB when the vertical irradiation is less than -10dB.

2. The double-layer resonant coupled absorber according to claim 1, characterized in that, The center of the first annular resistor pattern and the center of the second annular resistor pattern in the absorbing unit are projected onto the same point on the metal back plate.

3. A double-layer resonant coupled absorber according to claim 1, characterized in that, The first absorbing structure layer further includes a first thin film layer, and the second absorbing structure layer further includes a second thin film layer. The first annular resistor pattern is disposed on the first thin film layer, and the second annular resistor pattern is disposed on the second thin film layer. The thickness of the first thin film layer and the second thin film layer is 0.01mm-0.3mm.

4. A double-layer resonant coupled absorber according to claim 3, characterized in that, The first and second film layers are polyimide films or PET films.

5. A double-layer resonant coupled absorber according to claim 3, characterized in that, The first dielectric layer, the second dielectric layer, and the third dielectric layer are made of honeycomb material panels, lightweight polymethacrylimide foam boards, or polyvinyl chloride foam boards.

6. A double-layer resonant coupled absorber according to claim 1, characterized in that, The metal backplate, the first dielectric layer, the first microwave absorbing structure layer, the second dielectric layer, the second microwave absorbing structure layer, and the third dielectric layer are connected by an adhesive film layer, which is made of phenolic resin, epoxy resin, or unsaturated polyester resin.

7. A double-layer resonant coupled absorber according to claim 6, characterized in that, The adhesive film layer contains a fiber material, which may be glass fiber, carbon fiber, or organic fiber.

8. A double-layer resonant coupled absorber according to claim 3, characterized in that, The first and second annular resistor patterns are printed on the first and second thin film layers by screen printing.

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