A 2ghz-18ghz wave band high-efficiency wave absorber based on metamaterial and composite material

Abstract

This invention discloses a high-efficiency microwave absorber in the 2GHz-18GHz band based on metamaterials and composite materials, belonging to the field of electromagnetic microwave absorber technology. The absorber is composed of a fiber-reinforced laminate, a dielectric layer, a PET layer, and a metamaterial layer stacked together. The fiber-reinforced laminate consists of fibers embedded in a substrate, the substrate having a square cross-section, while the fiber portion uses materials such as SiC or glass with a grid-like cross-section. The dielectric layer uses the same material as the substrate of the fiber-reinforced laminate. The metamaterial layer uses an ITO conductive film with an etched circular pattern. This high-efficiency microwave absorber combining metamaterials and composite materials, through careful design, can achieve electromagnetic wave attenuation of over -20dB in the 2GHz-18GHz frequency band. The composite material portion achieves the absorption effect by converting electromagnetic energy into heat energy, while the metamaterial portion dissipates electromagnetic energy through resonance, thus achieving the absorption effect.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic absorber technology, and in particular to the combined design of metamaterials and composite materials. Existing technology

[0002] The commonly used microwave absorbing materials in the industry are composite materials composed of a carbon fiber skeleton and a carbon matrix (carbon particles, silicon carbide powder, etc.). This type of composite material faces challenges in achieving microwave absorption over a wide frequency band due to the difficulty in controlling the uniform mixing of the fiber and matrix materials. Furthermore, the random and discontinuous arrangement of the fibers in the composite material makes it impossible to pre-design material properties to achieve optimal microwave absorption characteristics. Secondly, the inability of the fibers to enhance the mechanical strength of the material in different directions results in insufficient structural strength, reducing its practicality. Finally, the manufacturing process of composite materials composed of carbon fiber skeletons and carbon matrices is complex and suffers from poor uniformity, leading to difficulties in quality control.

[0003] Metamaterial absorbers, a rapidly developing new type of absorber in the 21st century, can achieve near-perfect absorption of incident electromagnetic waves. Under normal circumstances, when electromagnetic waves are incident on a dielectric surface, reflection and transmission occur. However, metamaterial absorbers can significantly reduce and absorb electromagnetic waves, achieving zero transmission and near-zero reflection. The structure of a metamaterial absorber typically consists of three parts, similar to a sandwich structure: a top array of periodically arranged units with a specific shape, a middle dielectric substrate with high dielectric loss, and a bottom surface.

[0004] Compared to traditional composite absorbing materials, metamaterial absorbers have advantages such as thinness, small size, simple structure, high absorption rate, and wide absorption bandwidth. To improve the absorption bandwidth and absorption rate of absorbers in the microwave band, the industry generally pursues innovative breakthroughs in resonant structure design and dielectric material selection.

[0005] The development trend of broadband metamaterial absorbers shows that the absorption performance of these absorbers has been improved with the application of various new materials such as graphene and sheet resistivity films. However, existing transparent metamaterial absorbers generally suffer from drawbacks such as narrow absorption bandwidth and low absorption rate.

[0006] In summary, the problems with existing technologies are:

[0007] (1) The manufacturing of microwave absorbing composite materials requires high precision, but the quality control of microwave absorbing materials is currently difficult and the production process is relatively complex.

[0008] (2) Existing composite materials still lack structural strength after being made into finished products, which reduces their practicality.

[0009] (3) Existing metamaterial absorbers also have certain manufacturing problems, requiring high manufacturing precision, and generally have a narrow absorption frequency band and low absorption rate.

[0010] Purpose of the invention

[0011] In recent years, electromagnetic pollution, electromagnetic interference, and information leakage have become major factors to consider when designing modern scientific electronic instruments, antenna systems, and military electronic equipment. Therefore, research on highly efficient electromagnetic shielding materials and effective electromagnetic absorbing materials has received widespread attention. Among these, ceramic materials, such as SiC, Al2O3, and MgO, are widely used as electromagnetic absorbing materials due to their excellent electromagnetic wave absorption properties. Another widely used type of electromagnetic absorbing material is metamaterial absorbers.

[0012] The purpose of this patent is to combine composite absorbing materials with metamaterials to obtain a high-efficiency microwave absorber, which to some extent solves a series of problems encountered by the existing technologies. The absorbing material is composed of multiple layers of fiber-reinforced laminates and dielectric plates stacked together. The fiber-reinforced laminates are composed of continuous fibers arranged in a specific pattern embedded in the matrix material. The fibers serve to enhance the strength of the matrix and, together with the substrate, achieve a specific microwave absorption effect. Utilizing this laminated composite material structure, mechanical and chemical requirements can be easily met. Then, without changing the structural pattern, good microwave absorption can be achieved by determining a set of design parameters. Furthermore, by adding metamaterials to the layers, the absorption effect of the composite material in a certain frequency band can be improved, thereby achieving broadband and high-efficiency microwave absorption performance.

[0013] The invented technical solution is: a high-efficiency absorber for the 2GHz-18GHz band based on metamaterials and composite materials, characterized in that:

[0014] The absorber consists of an N-layer structure, with the bottom layer being the first layer and the top layer being the Nth layer.

[0015] Fiber-reinforced laminates consist of fibers embedded in a substrate. The substrate has a square cross-section with a side length of w, and the dielectric constant of the material used is ε∈(2.6,4.4). The fiber portion uses materials such as SiC and glass, and has a grid-like cross-section, with each of the four fibers having a width of x. i The center of the grid-shaped structure coincides with the center of the substrate, and it is a centrally symmetrical structure. Multiple fiber-reinforced laminates are stacked to form a composite material layer.

[0016] The material used for the dielectric layer is the same as the base material of the fiber-reinforced laminate.

[0017] The PET layer is made of PET.

[0018] The metamaterial layer uses an ITO conductive film, and the etched pattern is a ring.

[0019] The absorber is composed of the aforementioned fiber-reinforced laminate, dielectric layer, PET layer, and metamaterial layer stacked together, with respect to the number of layers N and the thickness h of each layer. i Fiber width x i By appropriately optimizing the inner and outer radii R1 and R2 of the ring and the impedance value Ω of the ITO conductive glass etched ring, an absorber that meets the absorption requirements can be obtained.

[0020] The high-efficiency absorber proposed in this invention, combining metamaterials and composite materials, can achieve electromagnetic wave attenuation of over -20dB in the 2GHz-18GHz frequency band through excellent design. The composite material part achieves the absorption effect by converting electromagnetic energy into heat energy, while the metamaterial part dissipates electromagnetic energy through resonance, thereby achieving the absorption effect. Attached Figure Description

[0021] Figure 1 This is an overall structural design diagram of an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the composite material layer structure according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the dielectric layer structure according to an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the PET layer structure according to an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the metamaterial layer structure according to an embodiment of the present invention.

[0026] Figure 6 This is a graph showing the real part of the dielectric constant of the fibers used in the first to fifth layers of the structure in this embodiment of the invention when the fiber axis is perpendicular to the direction of the electric field.

[0027] Figure 7 This is a graph showing the dielectric loss tangent of the fibers used in the first to fifth layers of the structure in this embodiment of the invention when the fiber axis is perpendicular to the direction of the electric field.

[0028] Figure 8 This is a graph showing the real part of the dielectric constant of the fibers used in the first to fifth layers of the structure in this embodiment of the invention when the fiber axis is parallel to the direction of the electric field.

[0029] Figure 9 This is a graph showing the dielectric loss tangent of the fibers used in the first to fifth layers of the structure in this embodiment of the invention when the fiber axis is parallel to the direction of the electric field.

[0030] Figure 10The high-efficiency microwave absorbing material combining metamaterials and composite materials in this embodiment of the invention exhibits its S-wave efficiency in the 2GHz-18GHz frequency band. 11 Data chart.

[0031] Implementation Examples

[0032] The following are real test data obtained through laboratory measurements, illustrating the microwave absorption performance of a high-efficiency absorber combining composite materials and metamaterials in the 2GHz-18GHz range.

[0033] A high-efficiency absorber was designed with the following layers: the first layer is 2.5 mm thick and the fiber width is 4.862 mm; the second layer is 1.773 mm thick and the fiber width is 3.479 mm; the third layer is 2.488 mm thick and the fiber width is 4.885 mm; the fourth layer is 1.141 mm thick and the fiber width is 1.787 mm; and the fifth layer is 1.537 mm thick and the fiber width is 0.5 mm.

[0034] The thickness of the sixth layer is 1.486 mm; the thickness of the seventh layer is 0.05 mm; the thickness of the eighth layer is 2.013 mm; and the thickness of the tenth layer is 2.5 mm.

[0035] The thickness of the ninth layer is 0.05mm, the outer radius of the etched ring is 4.885mm, the inner radius is 4.379mm, and the ring impedance is 143.9Ω.

[0036] For the aforementioned high-efficiency absorber combining composite materials and metamaterials, the electromagnetic wave tested was a plane wave with perpendicular incidence, the electric field polarization direction was x-polarization, and the frequency range was selected as 2GHz-18GHz.

[0037] The absorption effect diagram of the above-mentioned high-efficiency absorber is shown below. Figure 9 As shown, its S... 11 The reflectivity is generally below -10dB. This means the reflectivity of electromagnetic waves is below -20dB, and the reflected energy of incident electromagnetic waves on the material surface is close to 0%, which is negligible. Electromagnetic energy is attenuated to nearly 100% on the composite material surface through absorption.

[0038] The results show that a high-efficiency absorber combining composite materials and metamaterials exhibits excellent microwave absorption performance in the 2GHz-18GHz range, achieving the required wideband absorption capacity. Meanwhile, the experimental results in the embodiments fully demonstrate the correctness of the design method in this invention patent.

Claims

1. A metamaterial and composite material based high efficient wave absorber in 2-18 GHz band, characterized in that: The wave absorber is stacked from bottom to top by a composite layer, a dielectric layer, a PET layer, a dielectric layer, a metamaterial layer and a dielectric layer, wherein the bottom layer is the first layer and the top layer is the Nth layer; the composite layer is stacked by a plurality of fiber reinforced laminates; The fiber reinforced laminated plate is composed of fibers embedded in a base, the cross section of the base part is square, the side length is , the dielectric constant of the material used ; the cross section of the fiber part is a cross shape, the width of the four fibers is , the center of the cross shape structure coincides with the center of the base, and it is a central symmetric structure; The metamaterial layer uses an ITO conductive film, and the etching pattern is a circular ring; The material of the dielectric layer is consistent with the base material of the fiber reinforced laminate; wherein the fiber part of the fiber reinforced laminate is SiC; The wave absorber realizes electromagnetic wave attenuation of more than -20 dB in the frequency band of 2 GHz-18 GHz.

2. The metamaterial and composite based high efficiency wave absorber for 2-18 GHz band according to claim 1, characterized in that: The fiber part of the fiber reinforced laminate is glass.

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