Lightweight broadband wave-absorbing material
The lightweight broadband absorbing material with a three-dimensional structure and modular design solves the problems of poor fit to complex curved surfaces and insufficient frequency band coverage, achieving efficient wave absorption and stable installation of 6G communication systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN BOOM NEW MATERIALS
- Filing Date
- 2024-11-28
- Publication Date
- 2026-05-22
AI Technical Summary
Existing absorbing materials have poor adhesion to complex curved surfaces, making it difficult to meet the absorbing requirements of 6G communication systems in the 1GHz to 75GHz frequency band, and they are also difficult to install and fix and are prone to falling off.
The lightweight broadband absorbing material with a three-dimensional structure includes a reflective layer and four square ring absorbing units. The inner ring absorbing units form a self-similar structure and are filled with flexible absorbing foam. Combined with a modular design, it can achieve fit with irregular structures and efficient wave absorption.
It achieves excellent wave absorption performance in the 1GHz to 75GHz frequency band, with a material density of less than 0.5g/m3 and a thickness of less than 20mm. It can perfectly fit irregular structures and achieve a wave absorption efficiency of less than -10dB.
Smart Images
Figure CN122073331A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microwave absorbing materials technology, and specifically to a lightweight broadband microwave absorbing material. Background Technology
[0002] With the continuous advancement of science and technology, various advanced radars, detectors, and precision-guided weapons have emerged, posing a significant threat to military equipment. Correspondingly, to avoid radar detection, stealth technology has become a key research focus for various countries. Electromagnetic wave absorbing materials are a type of functional stealth material, commonly used on the surface of weapons to achieve a stealth effect. Traditional absorbing materials typically fall into two categories:
[0003] One is a rigid multilayer flat plate structure absorbing material, which can achieve good absorption of electromagnetic waves in the 1GHz to 40GHz frequency band, but it has poor flexibility and is difficult to fit tightly with complex curved structures.
[0004] Secondly, there are flexible wedge-structured absorbing materials, which are often attached to the floor or walls of darkrooms and can achieve good wave absorption, but they are very thick.
[0005] When these two electromagnetic wave absorbing materials are applied to objects with complex curved surfaces, they have problems such as poor fit and easy gap formation. On the one hand, this affects the absorption effect, and on the other hand, the difficulty in installation and fixing can cause the material to fall off or shift. Moreover, they can only achieve good absorption of electromagnetic waves in the frequency band of 1GHz to 40GHz, which is difficult to meet the absorption requirements of the 6G communication network operating frequency band of 1GHz to 75GHz.
[0006] With the development of 6G communication system technology, there is an urgent need for a thin, lightweight, and highly absorbent material that can effectively absorb waves in the 1GHz to 75GHz frequency band and perform well at different angles and positions, so as to provide a low-interference and stable environment for 6G communication systems. Summary of the Invention
[0007] The technical problem to be solved by the present invention is to provide a lightweight broadband absorbing material with good wave absorption effect in the range of 1 to 75 GHz, which meets the wave absorption requirements of 6G communication systems; it has the advantages of thinness, light weight, and perfect fit with various irregular structures, and can achieve good wave absorption effect at different angles and positions.
[0008] The present invention adopts the following technical solution:
[0009] A lightweight broadband absorbing material has a three-dimensional structure, including a reflective layer and four square ring absorbing units. The four square ring absorbing units are vertically arranged on the reflective layer to form a cavity structure with the reflective layer. An inner square ring absorbing unit is provided in the cavity structure to form a self-similar structure with the four square ring absorbing units. The gaps between the reflective layer, the four square ring absorbing units and the inner square ring absorbing units are filled with flexible absorbing foam.
[0010] The lightweight broadband absorbing material provided by this invention combines a self-similar structure formed by four square ring absorbing units and an inner square ring absorbing unit with a reflective layer. The four square ring absorbing units and the inner square ring absorbing units of the self-similar structure form an array of resistive rings, which couple to generate an electric dipole mode response. This allows electromagnetic waves to penetrate as much as possible into the material's interior and be lost as heat energy, improving absorption efficiency. Simultaneously, the four square ring units and the inner square ring units form an uneven absorbing layer in the vertical direction, increasing the refraction frequency of electromagnetic waves within the material. This achieves excellent absorption performance despite a relatively thin vertical thickness, enabling absorption efficiencies below -10dB in the 6G communication network operating frequency band from 1GHz to 75GHz. Furthermore, the self-similar square ring unit structure is a cavity structure filled with flexible foam, effectively reducing the material density to 0.5g / m³. 3 the following.
[0011] Optionally, the three-dimensional absorbing material is a modular structure. Each modular structure includes a reflective layer, four surrounding absorbing units, an inner absorbing material unit located in the cavity formed by the reflective layer and the surrounding absorbing units, and flexible absorbing foam filling the spaces between the reflective layer, the surrounding absorbing units, and the inner absorbing unit. The modular structures are detachably connected. The modular design of the absorbing material allows for adaptation to environmental requirements and facilitates fitting with irregularly shaped structures.
[0012] Optionally, the resistance of the four surrounding ring absorbing units and the inner ring absorbing unit is 350 to 400 Ω.
[0013] The resistance of the four square ring absorbing units and the inner square ring absorbing units is 350-400Ω, which is close to the vacuum resistance. This reduces the impedance difference at the interface of the absorbing material, allowing electromagnetic waves to enter the interior of the absorbing material as much as possible and be lost and converted into heat energy. High frequencies rely on the fusion of "resonance peaks". By dissipating this additional degree of freedom, a stronger broadband impedance matching is achieved.
[0014] Optionally, the number of the inner ring absorbing units is M. 2 There are 2 (M≥2) inner ring absorbing units, and the unit length of the inner ring absorbing unit is 1 / M times the length of the outer ring absorbing unit.
[0015] Optionally, the inner ring absorbing unit is a group of inner ring absorbing units that are self-similar to the four outer ring absorbing units. The inner ring absorbing unit group consists of several nested inner ring absorbing units, and the side length of the inner ring absorbing unit in the inner ring absorbing unit group decreases sequentially in the direction away from the four outer ring absorbing units.
[0016] Optionally, the four sides of the four sides of the surrounding ring absorbing unit are provided with detachable mounting structures to facilitate the assembly and disassembly of the modular three-dimensional structures of the absorbing material.
[0017] Optionally, the detachable mounting structure is one or more of the following: Velcro, protrusion mounting structure, and mortise and tenon structure.
[0018] The four-sided ring absorbing unit adopts a detachable installation structure, which can realize the modular three-dimensional structure absorbing material to be disassembled and installed according to different irregular structures, so that the absorbing material can meet the usage requirements of different irregular structures.
[0019] Optionally, the four sides of the four-sided ring absorbing unit and the four sides of the inner ring absorbing unit are structural layers of annular conductive foam embedded in flexible blank foam, with the annular conductive foam and the flexible blank foam arranged along the same central axis.
[0020] Optionally, the resistance of the conductive foam is 350Ω to 440Ω.
[0021] Optionally, the conductive foam is a foam in which conductive powder is uniformly added to blank foam, and the conductive powder is one or more of metal nanoparticles, metal fibers and graphene.
[0022] Optionally, the blank foam is one of EVA foam, PI foam, IXPE foam, and PU foam, and the density of the blank foam is 0.1 g / m³. 3 ~0.5g / m 3 .
[0023] Optionally, the side length of the four-sided ring absorbing unit is 6mm to 15mm, and the height is 5mm to 20mm. The length and height of the ring-shaped conductive foam are both shorter than the side length and height of the four-sided ring absorbing unit, and the thickness of the ring-shaped conductive foam in the four-sided ring absorbing unit is the same as the thickness of the four-sided ring absorbing unit.
[0024] Optionally, the inner ring absorbing unit is a similar structure to the four outer ring absorbing units, with the length, height, and thickness scaled down proportionally.
[0025] Optionally, the flexible microwave absorbing foam is one of rubber, EVA foam, PI foam, IXPE foam, and PU foam doped with a microwave absorbing agent.
[0026] Optionally, the flexible microwave absorbing foam is a foam formed by adding an absorbent, wherein the absorbent is one or more of carbon fiber, carbon nanotubes, silicon carbide, graphene, carbon powder, conductive polymer polyaniline, polypyrrole, ferrite, and barium titanate; the density of the flexible microwave absorbing foam is 0.1 g / m³. 3 ~0.5g / m 3 The dielectric constant is 1.1 to 2.0, and the loss tangent is ≥0.1.
[0027] Optionally, the reflective layer is a carbon fiber felt layer or a silicon carbide fiber layer.
[0028] Optionally, the compression ratio of the flexible absorbing foam is >60%.
[0029] The beneficial effects that this invention can achieve are:
[0030] (1) This invention provides a lightweight broadband absorbing material that combines a self-similar structure stacked on top of each other with a flexible absorbing foam. On the one hand, the array of resistive rings will couple to generate an electric dipole mode response to achieve impedance matching. On the other hand, the absorbing foam achieves dielectric and resistive losses, thereby achieving stronger broadband impedance matching, thus meeting the absorbing requirements of the 6G communication network operating frequency band of 1GHz to 75GHz.
[0031] (2) The lightweight broadband absorbing material provided by the present invention adopts a modular three-dimensional structure, which has strong adaptability and can effectively fit with various irregular structures.
[0032] (3) The flexible, lightweight, broadband absorbing material provided by this invention has a material density of <0.5 g / m³. 3 When the thickness is less than 20mm, it can achieve a wave absorption effect of -10dB in the operating frequency range of 1GHz to 75GHz. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the structure of the lightweight broadband absorbing material in Example 1;
[0034] Figure 2 This is a schematic diagram of the four-sided ring absorbing unit and the reflective layer in Example 1.
[0035] Figure 3 This is a schematic diagram of the inner ring absorbing unit in Example 1.
[0036] Figure 4 This is a schematic diagram of the structure without flexible absorbing foam in Example 2.
[0037] Figure 5 This is a test diagram of the absorption effect in Example 1.
[0038] Figure 6The image shows the absorption effect test result of Example 2.
[0039] Figure 7 This is a test diagram of the absorption effect in Comparative Example 1.
[0040] Figure 8 The test diagram shows the absorption effect of Comparative Example 2.
[0041] In the diagram, 1 is a surrounding ring of absorbing units, 2 is flexible absorbing foam, 3 is a reflective layer, 21 is a ring-shaped conductive flexible foam, and 22 is a flexible blank foam. Detailed Implementation
[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0043] Example 1:
[0044] like Figure 1 , Figure 2 , Figure 3 As shown, the lightweight broadband absorbing material provided in this embodiment has a three-dimensional structure, including a reflective layer 3 and four square ring absorbing units 1. The four square ring absorbing units 1 are vertically disposed on the reflective layer 3 to form a cavity structure with the reflective layer 3. An inner square ring absorbing unit is provided in the cavity structure to form a self-similar structure with the four square ring absorbing units 1. The gaps between the reflective layer, the four square ring absorbing units and the inner square ring absorbing units are filled with flexible absorbing foam 2.
[0045] In this embodiment, the side length of the four outer ring absorbing units 1 is 10cm, the height is 6cm, and the number of inner ring absorbing units is 4 (2 2 The system comprises: an inner ring absorbing unit with a side length of 5cm, a reflective layer 3 being a carbon fiber layer, and a four-sided ring absorbing unit consisting of a ring-shaped conductive foam embedded in a flexible blank EVA foam structure, with the ring-shaped conductive foam and the flexible blank EVA foam arranged coaxially. The conductive ring of the four-sided ring absorbing unit has a side length of 8cm, a ring width of 2cm, and a resistance of 377Ω. The inner ring absorbing unit also consists of a ring-shaped conductive foam embedded in a flexible blank EVA foam structure, with a side length of 4cm, a ring width of 0.5cm, and a resistance of 377Ω. The flexible absorbing foam 2 is a foam formed by adding an absorbent, which is a mixture of carbon fiber and graphene, with the carbon fiber and graphene accounting for 0.8% and 0.1% of the total weight of the foam, respectively. The conductive foam is an EVA foam in which a mixture of silver nanoparticles and carbon nanotubes is uniformly added to the blank foam.
[0046] The absorption performance of a lightweight broadband absorbing material provided in Example 1 was tested, such as... Figure 5 As shown, the lightweight high-frequency absorbing material provided in Example 1 can achieve good absorption in the 1-75GHz frequency band, with absorption efficiency reaching below -10dB. In the 5-75GHz frequency band, the electromagnetic wave absorption efficiency can reach -16dB, and the maximum absorption efficiency can reach -26dB.
[0047] Example 2:
[0048] This embodiment provides a lightweight broadband absorbing material, which differs from Embodiment 1 only in that the side lengths of the four outer ring absorbing units and the ring-shaped conductive foam are different, and the number of inner ring absorbing units is 9 (3 squared). Figure 4 As shown.
[0049] In this embodiment, the side length of the four outer ring absorbing units is 12cm, the height is 9cm, and the number of inner ring absorbing units is 9 (3). 2 The system consists of three phases: an inner ring absorbing unit with a side length of 4cm, a carbon fiber reflective layer 3, and a four-phase ring absorbing unit with a structure layer consisting of a ring-shaped conductive foam embedded in flexible blank EVA foam. The ring-shaped conductive foam and the flexible blank EVA foam are coaxially arranged. The conductive ring of the four-phase ring absorbing unit has a side length of 9cm, a ring width of 2cm, and a resistance of 377Ω. The inner ring absorbing unit has a side length of 4cm, and is a structure layer consisting of a ring-shaped conductive foam embedded in flexible blank EVA foam. The conductive ring of the inner ring absorbing unit has a side length of 3cm, a ring width of 0.5cm, and a resistance of 377Ω. Flexible absorbing EVA foam is filled in the gaps between the reflective layer, the four surrounding ring absorbing units, and the inner ring absorbing units. The flexible absorbing foam is foamed with the addition of an absorbent, which is a mixture of carbon fiber and graphene, wherein the amount of carbon fiber and graphene accounts for 0.8% and 0.1% of the total weight of the foam, respectively. The conductive foam is EVA foam in which a mixture of silver nanoparticles and carbon nanotubes is uniformly added to blank foam.
[0050] The absorption performance of a flexible, lightweight, broadband absorbing material provided in Example 2 was tested, such as... Figure 6 As shown, the flexible, lightweight, high-frequency absorbing material provided in Example 2 can achieve good absorption in the 1-75GHz frequency band, with absorption efficiencies all below -10dB. In the 5-75GHz frequency band, the electromagnetic wave absorption efficiency can reach -20dB, and the maximum absorption efficiency can reach -42dB.
[0051] Comparative Example 1:
[0052] The lightweight broadband absorbing material provided in this comparative example differs from Example 1 only in that the number of inner square ring absorbing units is one.
[0053] Performance tests are shown in Figure 7. Figure 7 As shown, the electromagnetic wave absorption effect is not very good. The absorption effect is not very good in the frequency bands of 1-18GHz, 35-42GHz, and 47-57GHz, and can only reach -5dB.
[0054] Comparative Example 2:
[0055] The lightweight broadband absorbing material provided in this comparative example differs from Example 1 only in that it does not have a filling absorbing foam layer. The performance test is shown in Figure 8. The absorption effect of electromagnetic waves in the low frequency band of 1-20GHz is poor, only -5dB.
Claims
1. A lightweight broadband absorbing material, having a three-dimensional structure, comprising a reflective layer and four surrounding ring-shaped absorbing units, characterized in that, The four-sided ring absorbing units are vertically arranged on the reflective layer to form a cavity structure with the reflective layer. In the cavity structure, there is an inner ring absorbing unit that forms a self-similar structure with the four-sided ring absorbing units. The gaps between the reflective layer, the four-sided ring absorbing units, and the inner ring absorbing units are filled with flexible absorbing foam.
2. The lightweight broadband absorbing material according to claim 1, characterized in that, The three-dimensional absorbing material is a modular structure. Each modular structure includes a reflective layer, four surrounding ring absorbing units, an inner ring absorbing material unit located in the cavity formed by the reflective layer and the four surrounding ring absorbing units, and flexible absorbing foam filling the spaces between the reflective layer, the four surrounding ring absorbing units, and the inner ring absorbing unit. The modular structures are detachably connected to each other.
3. A lightweight broadband absorbing material according to claim 1 or 2, characterized in that, The resistance of the four square ring absorbing units and the inner square ring absorbing unit is 350-400Ω.
4. The lightweight broadband absorbing material according to claim 3, wherein the number of the inner square ring absorbing units is M. 2 There are 2 (M≥2) units, and the unit length of the inner ring absorbing unit is 1 / M times the length of the four outer ring absorbing units.
5. The lightweight broadband absorbing material according to claim 3, characterized in that, The inner ring absorbing unit is a group of inner ring absorbing units that are self-similar to the four outer ring absorbing units. The inner ring absorbing unit group consists of several nested inner ring absorbing units. The side length of the inner ring absorbing unit in the inner ring absorbing unit group decreases sequentially in the direction away from the four outer ring absorbing units.
6. The lightweight broadband absorbing material according to claim 2, characterized in that, The four sides of the four sides of the absorbing unit are provided with detachable mounting structures, which are one or more of the following: Velcro, protrusion mounting structure, and mortise and tenon structure.
7. The lightweight broadband absorbing material according to claim 3, characterized in that, The four sides of both the outer and inner ring absorbing units are structured layers of annular conductive foam embedded in flexible blank foam, and the resistance of the conductive foam is 350Ω to 440Ω.
8. The lightweight broadband absorbing material according to claim 7, characterized in that, The conductive foam is a foam in which conductive powder is uniformly added to a blank foam. The conductive powder is one or more of metal nanoparticles, metal fibers, and graphene.
9. The lightweight broadband absorbing material according to claim 8, characterized in that, The side length of the four-sided ring absorbing unit is 6mm to 15mm, and the height is 5mm to 20mm. The length and height of the ring-shaped conductive foam are both shorter than the side length and height of the four-sided ring absorbing unit. The thickness of the ring-shaped conductive foam of the four-sided ring absorbing unit is the same as the thickness of the four-sided ring absorbing unit.
10. A lightweight broadband absorbing material according to claim 3, characterized in that, The flexible microwave absorbing foam is one of the following: rubber, EVA foam, PI foam, IXPE foam, and PU foam doped with microwave absorbing agents.