Dual-mode metasurface for realizing reflection and absorption based on inflatable structure

Abstract

The invention discloses a dual-mode metasurface for realizing reflection and absorption based on an inflatable structure, which comprises a base body formed by sequentially compounding a conductive fiber patch, a fabric dielectric layer and conductive fiber cloth, a conductive film is distributed on the conductive fiber patch, and a PET (Polyethylene Terephthalate) film is wrapped outside the base body with the conductive film; when the conductive thin film is attached to the conductive fiber patch, the dual-mode metasurface is a wave absorbing face; and when the PET film is inflated with gas and then bulges, and the conductive film is separated from the conductive fiber patch, the dual-mode metasurface is a reflecting surface. By introducing the controllable inflation layer, combining the common fabric, the conductive fiber material and the carbon-coated film, flexible switching between an electromagnetic wave absorption mode and a reflection mode is realized by utilizing dynamic change of an inflation state, meanwhile, the flexibility and the light weight of the structure are ensured, flexible regulation and control on electromagnetic waves within a specific frequency range are realized, and the electromagnetic wave absorption and reflection effect is improved. The method is widely applied to the fields of radar stealth, communication system optimization, electromagnetic compatibility design, infrared stealth and the like.

Description

Technical Field

[0001] The invention relates to a metasurface structure for realizing dual-mode switching of reflection and absorption based on an air-filled structure, and belongs to the technical field of metamaterials. Background Art

[0002] As emerging means of electromagnetic wave control, metamaterials and metasurface technologies have shown great potential in functional fields such as absorption, reflection, and transmission. Metasurfaces achieve precise control of the phase, amplitude, and polarization of electromagnetic waves by designing subwavelength unit structures, and are widely used in radar stealth, electromagnetic shielding, and communication system optimization. However, existing metasurface technology still faces a series of problems in practical applications: single functional mode, structural rigidity limitations, high manufacturing costs, and difficulty in balancing absorption and reflection performance. These limitations are particularly prominent in dynamic and complex electromagnetic environments.

[0003] First, the functional mode is single and difficult to dynamically control. Traditional metasurfaces are usually optimized for specific functions during design, such as wave absorption or reflection, and their functional modes are difficult to change once they are determined. This fixed design is not flexible enough in a dynamic electromagnetic environment. Existing control methods, such as loading varactor diodes or using phase change materials, can achieve a certain degree of dynamic adjustment, but the design is complex, the cost is high, and the response speed is limited.

[0004] Second, the rigid structural design limits flexible applications. Metasurfaces usually use metal or rigid dielectric substrates. Although these materials have excellent conductivity and mechanical strength, they lack flexibility, which limits their application scenarios. Flexible metasurfaces have gradually attracted attention due to their light weight, bendability, and easy integration, but they still face many challenges in functional design and performance optimization.

[0005] Third, electromagnetic and infrared stealth has high manufacturing costs and complex processes. The manufacturing of existing metasurfaces usually relies on nanoscale precision processing technology, such as metal film etching, nanoimprinting, or the use of ITO (Indium Tin Oxide) materials to achieve electromagnetic and infrared effects. Although these processes can achieve high-performance designs, they are complex and expensive to process, and are not suitable for large-scale manufacturing. At the same time, many metasurfaces rely on rare metals or composite materials (such as gold, silver, carbon nanotubes, etc.), which further limits the feasibility of their commercial applications.

[0006] Fourth, it is difficult to take into account both absorption and reflection performance. The realization of absorption and reflection functions usually requires completely different structural designs: the absorption function relies on the electromagnetic energy loss of the material, while the reflection function requires high conductivity to maximize the reflected energy. Existing designs find it difficult to take both into account in the same structure, let alone achieve dynamic switching. Even though some mechanical control methods try to achieve mode switching by adjusting the arrangement of patches, the problems of structural complexity and mechanical stability have not been effectively solved. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a dual-mode metasurface that can meet the flexible switching of electromagnetic wave absorption and reflection modes while ensuring the flexibility and lightness of the structure.

[0008] In order to solve the above problems, the present invention provides a dual-mode metasurface that realizes reflection and absorption based on an inflatable structure, which includes a substrate composed of a conductive fiber patch, a fabric dielectric layer, and a conductive fiber cloth in sequence, wherein a conductive film is distributed on the conductive fiber patch, and a PET film is wrapped outside the substrate with the conductive film; when the conductive film and the conductive fiber patch are bonded together, the dual-mode metasurface is an absorbing surface; when the PET film is filled with gas and bulges, separating the conductive film and the conductive fiber patch, the dual-mode metasurface is a reflecting surface.

[0009] Preferably, the conductive film is a conductive PE film or a carbon-coated film.

[0010] Preferably, the conductive fiber patch and the conductive fiber cloth are made of the same or different materials.

[0011] Preferably, the fabric medium layer is made of felt.

[0012] Preferably, a plurality of the conductive fiber patches are arranged in an array structure on a conductive fiber cloth to form a square electromagnetic band gap structure (EBG, Electromagnetic Band Gap), and the square electromagnetic band gap structure is wrapped with a PET film.

[0013] More preferably, the square electromagnetic band gap structure is provided with an air inlet and an air outlet, and a reconfigurable metasurface with switchable reflection and absorption functions is realized through a mechanical dynamic process of inflation and deflation.

[0014] Preferably, a conductive film in the shape of an X is provided on the edge of each conductive fiber patch, the conductive films in the shape of an X on adjacent conductive fiber patches form a double X-shaped structure, and the conductive fiber patches on the four corners are not provided with conductive films on the edges adjacent to another conductive fiber patch.

[0015] More preferably, the square electromagnetic band gap structure is provided with 12×12 conductive fiber patches, which includes 11×11 conductive films of a double-geometry structure.

[0016] Preferably, the reflective surface achieves 0-degree phase reflection at 2.4 GHz, which is used to improve the directivity and gain of the antenna. In addition, the dual-mode metasurface has a thermal infrared stealth function by utilizing the flow of filled gas to discharge heat; the absorbing surface utilizes the strong coupling principle for electromagnetic stealth or electromagnetic shielding.

[0017] The present invention introduces a controllable air-filled layer, combines ordinary fabrics, conductive fiber materials and carbon-coated films, and utilizes the dynamic change of the air-filled state to realize the flexible switching of electromagnetic wave absorption and reflection modes, while ensuring the flexibility and lightness of the structure, and realizing the flexible regulation of electromagnetic waves within a specific frequency range. It is widely applicable to the fields of radar stealth, communication system optimization, electromagnetic compatibility design and infrared stealth. The present invention uses the concept and theory of metamaterial reflection and absorption to design a method of introducing a controllable air-filled layer, combining ordinary fabrics, conductive fiber materials, carbon-coated films and PET (polyethylene terephthalate) films, to realize the flexible regulation of electromagnetic waves within a specific frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of the dual-mode metasurface provided by the present invention;

[0019] Figure 2 It is a structural schematic diagram of a square electromagnetic bandgap structure;

[0020] Figure 3 A schematic diagram of the use of the dual-mode metasurface provided by the present invention as a wave absorbing surface in an uninflated state;

[0021] Figure 4 This is a front view of the dual-mode metasurface provided by the present invention as a reflective surface in an inflated state;

[0022] Figure 5 for Figure 4 A top view of

[0023] Figure 6 is a schematic diagram of a monopole antenna;

[0024] Figure 7 The S11 parameter result diagram of the dual-mode metasurface provided by the present invention as a wave-absorbing metasurface in an uninflated state. As a wave-absorbing metasurface, the S11 can reach -29.91dB (peak absorption rate 99.7%) at 2.4GHz, and achieve 90% absorption rate within a bandwidth of 120MHz (S11 is less than -10dB);

[0025] Figure 8 The radiation pattern of the dual-mode metasurface provided by the present invention without a loaded metasurface;

[0026] Fig. 9 The monopole antenna radiation pattern of the dual-mode metasurface provided by the present invention after being loaded and inflated;

[0027] Fig.10 This is an infrared viewing angle image of the dual-mode metasurface provided by the present invention using airflow to discharge heat when inflated. DETAILED DESCRIPTION

[0028] In order to make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0029] Example

[0030] like Figure 1 As shown, a dual-mode metasurface based on an inflatable structure for realizing reflection and absorption is provided in this embodiment, which includes a substrate composed of a conductive fiber patch (as a reflective patch), a fabric dielectric layer, and a conductive fiber cloth in sequence. A conductive film is distributed on the conductive fiber patch. A plurality of conductive fiber patches are arranged in a 12×12 array structure on a conductive fiber cloth to form a square electromagnetic bandgap structure. The square electromagnetic bandgap structure is wrapped with a PET film. The square electromagnetic bandgap structure is provided with an air inlet and an air outlet. A reconfigurable metasurface with switchable reflection and absorption functions is realized through the mechanical dynamic process of inflation and deflation. A conductive film in the shape of a letter “J” is provided on the edge of each conductive fiber patch. The conductive films in the shape of a letter “J” on adjacent conductive fiber patches form a double-shaped structure. The conductive fiber patches on the four corners are not provided with conductive films on the edges of another conductive fiber patch. Then, the square electromagnetic bandgap structure includes 11×11 conductive films in a double-shaped structure, as shown in FIG. Figure 2 shown.

[0031] The conductive film is made of conductive PE film, and the conductive fiber patch and conductive fiber cloth are made of the same material (both are Figure 1 The fabric dielectric layer is made of felt.

[0032] In order to achieve lightness and flexibility, the above-mentioned inflatable reconfigurable metasurface uses conductive fiber materials as the floor and reflective patch, uses ordinary fabric with a dielectric constant of 1.2, a loss tangent of 0.005, and a thickness of 2mm as the dielectric layer, and uses a carbon-coated film material with a square resistance of 20Ω / sq and 377Ω for impedance matching. When not inflated, the carbon-coated film is close to the square reflective patch. Using the principle of strong coupling, a strong coupling current is generated on the carbon-coated film and then converted into heat energy to achieve the absorption effect, as an absorbing metasurface. When filled with gas, the carbon-coated film layer of this metasurface moves up and separates from the reflective patch, acting as a reflective surface to improve the directivity and gain of the antenna. In addition, the flow of the filled gas is used to discharge heat to achieve thermal infrared stealth function.

[0033] The specific size parameters of the above-mentioned inflatable reconfigurable metasurface are shown in Table 1.

[0034] Table 1

[0035] L D H W C T 58mm 8mm 2mm 52mm 2.5mm 17.25mm

[0036] When the conductive film and the conductive fiber patch are bonded together, the dual-mode metasurface is an absorbing surface, which uses the strong coupling principle to be used for electromagnetic stealth or electromagnetic shielding (such as Figure 3The absorption effect of the inflatable reconfigurable metasurface of the present invention when not inflated is tested by using two standard horn antennas, one as a transmitting antenna and the other as a receiving antenna. The results are shown in FIG. Figure 7 As shown, as an absorbing metasurface, S11 can reach -29.91dB (peak absorption rate 99.7%) at 2.4GHz, and achieve 90% absorption rate within a bandwidth of 120MHz (S11 less than -10dB). Figure 8 The implementation method of the inflatable reconfigurable metasurface of the present invention as a reflective metasurface when inflated is demonstrated. When filled with air, the conductive PE film moves upward with the expansion of the PET film and separates from the conductive fiber patch. A monopole antenna with an operating frequency of 2.4 GHz is placed on the upper surface of the reflective patch. The CST (Computer Simulation Technology) software is used to simulate the situation of the metasurface with a single antenna and the addition of the inflated metasurface of the present invention. The specific results are as follows: Figure 7-9 As shown. Among them, Figure 8 When there is no reflector, the maximum gain of the monopole antenna is 3.271dBi at 2.4GHz. Fig. 9 When the inflated metasurface of this example is added behind the antenna, the maximum gain of the monopole antenna increases to 7.349 dBi at 2.4 GHz. This embodiment significantly improves the radiation effect of the antenna.

[0037] A monopole antenna is placed between the PET film and the reflective patch, such as Figure 4-6 When the PET film is filled with gas and swells, separating the conductive film from the conductive fiber patch, the dual-mode metasurface becomes a reflective surface, which achieves 0-degree phase reflection at 2.4 GHz, thereby improving the directivity and gain of the antenna. In addition, the dual-mode metasurface has a thermal infrared stealth function by utilizing the flow of the filled gas to discharge heat. Fig.10 The infrared perspective shows the process of airflow entering the inflatable reconfigurable metasurface of the present invention and discharging heat when it is inflated. As the air enters, the surface temperature drops significantly, thus achieving an infrared stealth effect.

Claims

1. A dual-mode metasurface based on an inflatable structure for achieving reflection and absorption, characterized in that: It includes a substrate composed of a conductive fiber patch, a fabric dielectric layer, and a conductive fiber cloth in sequence, wherein a conductive film is distributed on the conductive fiber patch, and a PET film is wrapped outside the substrate with the conductive film; when the conductive film and the conductive fiber patch are attached to each other, the dual-mode metasurface is an absorbing surface; when the PET film is filled with gas and bulges, separating the conductive film and the conductive fiber patch, the dual-mode metasurface is a reflecting surface.

2. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 1, characterized in that: The conductive film is a conductive PE film or a carbon-coated film.

3. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 1, characterized in that: The conductive fiber patch and the conductive fiber cloth are made of the same or different materials.

4. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 1, characterized in that: The fabric medium layer is made of felt.

5. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 1, characterized in that: A plurality of the conductive fiber patches are arranged in an array structure on a conductive fiber cloth to form a square electromagnetic band gap structure, and a PET film is wrapped outside the square electromagnetic band gap structure.

6. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure as claimed in claim 5, characterized in that: The square electromagnetic band gap structure is provided with an air inlet and an air outlet.

7. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 5, characterized in that: The edge of each conductive fiber patch is provided with a conductive film in the shape of a cross, and the conductive films in the shape of a cross on adjacent conductive fiber patches form a double cross-shaped structure. The conductive fiber patches on the four corners are not provided with conductive films on the edges adjacent to another conductive fiber patch.

8. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to claim 6, characterized in that: The square electromagnetic band gap structure is provided with 12×12 conductive fiber patches, which includes 11×11 conductive films of a double-geometry structure.

9. The dual-mode metasurface for realizing reflection and absorption based on an inflatable structure according to any one of claims 1 to 8, characterized in that: The reflective surface achieves 0-degree phase reflection at 2.4 GHz, which is used to improve the directivity and gain of the antenna. In addition, the dual-mode metasurface has a thermal infrared stealth function by utilizing the flow of filled gas to discharge heat. The absorbing surface utilizes the strong coupling principle for electromagnetic stealth or electromagnetic shielding.

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