Pointed cone metamaterial composite wave-absorbing structure and preparation method thereof

Abstract

The invention relates to the technical field of electromagnetic wave-absorbing materials, in particular to a pointed cone metamaterial composite wave-absorbing structure and a preparation method thereof. The pointed cone metamaterial composite wave-absorbing structure comprises a reflecting layer, a wave-absorbing array pointed cone structure, a wave-transmitting layer and a metamaterial layer. The wave-absorbing array pointed cone structure is divided into a conical cone structure and a wave-absorbing base structure, and the wave-transparent layer is divided into a filling structure layer and a wave-transparent skin. The reflecting layer is arranged below the wave-absorbing base structure, the wave-transparent skin is arranged above the conical cone structure, the filling structure layer is arranged in a gap between the conical cone structure and the wave-transparent skin structure, and the metamaterial layer is located above the wave-transparent skin. The whole wave-absorbing structure is simple, the wave-absorbing performance is adjusted by modifying the periodic array pointed cone structure and the metamaterial structure, and the prepared wave-absorbing structure is thin in thickness, light in mass and excellent in wave-absorbing effect at the low frequency of 0.3-2 GHz.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic absorbing materials, and in particular to a pointed cone metamaterial composite absorbing structure and a preparation method thereof. Background Art

[0002] Currently, traditional absorbing structures mostly use multi-layer dielectric plates for impedance matching to achieve the absorbing effect. However, this structure is often thick, and the multi-layer matching structure has poor mechanical properties and is complex to manufacture. Summary of the Invention

[0003] Compared with the multi-layer dielectric plate structure, the array pointed cone structure is thinner and lighter, and the low-frequency absorption performance is better after using the metamaterial structure, because the present invention proposes a pointed cone metamaterial composite absorbing structure, which can meet the requirements of having excellent absorption effects in the low-frequency band of 0.3 to 2 GHz.

[0004] According to one aspect of the present application, a pointed cone metamaterial composite wave absorbing structure is provided, wherein the pointed cone metamaterial composite wave absorbing structure comprises a reflective layer 10, a wave absorbing array pointed cone structure 20, a wave-transmitting layer 30, and a metamaterial layer 40;

[0005] The wave absorbing array pointed cone structure 20 includes a cone structure 21 and a wave absorbing base 22;

[0006] The wave-transmitting layer 30 includes a filling structure layer 31 and a wave-transmitting skin 32;

[0007] The reflective layer 10 is disposed below the absorbing base 22;

[0008] The wave-transmitting skin 32 is arranged above the conical structure 21;

[0009] The filling structure layer 31 is arranged in the gap between the conical structure 21 and the wave-transmitting skin 32;

[0010] The metamaterial layer 40 is located above the wave-transmitting skin 32 .

[0011] The material of the reflective layer 10 is a carbon fiber composite material;

[0012] The material of the wave absorbing array cone structure 20 is carbonyl iron-epoxy resin;

[0013] The material of the filling structure layer 31 is epoxy resin;

[0014] The material of the wave-transmitting skin 32 is one of quartz prepreg and aramid prepreg;

[0015] The metamaterial layer 40 is made of metal.

[0016] The bottom radius of the conical cone structure 21 is 3-5 mm, and the height is 2-4 mm.

[0017] The height of the wave-absorbing base 22 is 1-3 mm.

[0018] The sharp cone in the wave-absorbing array sharp cone structure 20 is horizontally and regularly arranged.

[0019] The thickness of the wave-transparent skin 32 is 0.05-0.15 mm.

[0020] The thickness of the reflective layer 10 is 0.4-0.6 mm.

[0021] The thickness of the metamaterial layer 40 is 20-50 um.

[0022] The structure of the metamaterial layer 40 is selected from at least one of a circular cross, a circular ring, and a square ring.

[0023] According to another aspect of the present application, a preparation method of the above-mentioned sharp cone metamaterial composite wave-absorbing structure is provided, comprising the following steps:

[0024] The carbon fiber prepreg is accurately laid on the bottom layer of the mold according to the design requirements, ensuring no bubbles and wrinkles, and then 0.1 Mpa pressure is given for preliminary curing for 24 h at room temperature to ensure that the prepreg is tightly combined with the mold;

[0025] After the bottom layer is completely cured, it is placed in the mold, and a layer of carbonyl iron-epoxy resin with a thickness of 0.1-0.3 mm is evenly applied on the carbon fiber prepreg and cured; after the carbonyl iron-epoxy resin layer is completely cured, an ultrafast laser is used to accurately cut out the shape of the cone on the carbonyl iron-epoxy resin, and attention is paid to protect the surrounding materials and structures from being affected by the laser processing;

[0026] After cutting is completed, it is placed back into the mold; the epoxy resin and its curing agent are accurately measured and mixed, stirred uniformly, and all bubbles are extracted using a vacuum pump; after there are no bubbles in the mixture, it is slowly poured into the mold, and special attention is paid to cover the cone area and ensure that the epoxy resin can fully penetrate and fill the entire space, and a scraper or other tool is used to assist in applying and filling the gap;

[0027] After the epoxy resin is completely cured, the quartz prepreg wave-transparent skin is bonded to the other side of the epoxy resin layer using an epoxy film;

[0028] The metal sheet is cut using an ultrafast laser, and the required shape is cut out, the metal sheet is firmly pasted or connected to the cured composite material structure using an adhesive, and during the process, it is ensured that the pasting surface is clean, flat, and no bubbles are generated, and the sharp cone metamaterial composite wave-absorbing structure is obtained.

[0029] The wave-absorbing structure of the present invention has good precision, light weight, and thin thickness, and has excellent wave-absorbing effect in the frequency band of 0.3 to 2 GHz, and can be applied to the application of electromagnetic wave-absorbing materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the cone metamaterial composite absorbing structure.

[0031] Figure 2 Schematic diagram of the pointed cone metamaterial composite absorbing structure unit.

[0032] Figure 3 Schematic diagram of the cone structure unit of the absorbing array.

[0033] Figure 4 Schematic diagram of the wave-transmitting structure.

[0034] Figure 5 This is a comparison chart of the reflectivity of the pointed cone metamaterial composite absorbing structure and the traditional layered dielectric plate structure. DETAILED DESCRIPTION

[0035] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0036] Example 1

[0037] See also Figure 1 、 Figure 2 、 Figure 3 and Figure 4 A conical metamaterial composite absorbing structure includes a reflective layer 10, a conical absorbing array structure 20, a transparent layer 30, and a metamaterial layer 40. The conical absorbing array structure 20 is divided into a conical structure 21 and an absorbing base 22, and the transparent layer 30 is divided into a filling structure layer 31 and a transparent skin 32. The reflective layer 10 is arranged below the absorbing base 22, and the transparent skin 32 is arranged above the conical structure 21. The filling structure layer 31 is arranged in the gap between the conical structure 21 and the transparent skin 32, and the metamaterial layer 40 is located above the transparent skin 32.

[0038] In the embodiment of the present invention, the height of the cone 21 is 3 mm. The pointed cone structure increases the reflective area of ​​the absorbing material and allows for continuous reflection of electromagnetic waves between the areas formed by two adjacent cones, thereby reducing both reflection and absorption losses. This allows the pointed cone metamaterial composite absorbing structure of the present invention to achieve broadband absorption at low frequencies. Furthermore, compared to pure absorbing dielectric plate structures, the present invention offers the advantage of reduced weight.

[0039] In an embodiment of the present invention, reflective layer 10 is configured as a carbon fiber composite reflective layer. This carbon fiber composite reflective layer isolates the absorbing material layer from the outside world, thereby improving the mechanical and thermal properties of the absorbing structure. In this embodiment of the present invention, the matrix of the carbon fiber composite reflective layer is epoxy resin.

[0040] In the embodiment of the present invention, the thickness of the absorbing base 22 is 3.5 mm. If the absorbing layer is too thin, the absorbing effect of the absorbing array cone structure will be weak at low frequencies. If the absorbing layer is too thick, the absorbing array cone structure will be too heavy, making it difficult to achieve the goal of lightweight absorbing array cone structure. In the embodiment of the present invention, the conical structure 21 and the absorbing base 22 are both made of a carbonyl iron-epoxy resin composite material, and the resin is cured to form an integrated structure.

[0041] In an embodiment of the present invention, the filling structure layer 31 is made of epoxy resin.

[0042] In an embodiment of the present invention, the material of the wave-transmitting skin 32 is quartz prepreg.

[0043] In the embodiment of the present invention, the metamaterial layer is a circular cross, made of metal materials, with a thickness of 20 μm. In the circular cross structure, the circular structure and the cross structure are intersecting structures, the circle radius is 7 mm, the cross width is 1 mm, and the length is 5 mm.

[0044] In the embodiments of the present invention, all raw materials used are purchased from the market.

[0045] In an embodiment of the present invention, the carbon fiber prepreg is precisely laid on the bottom layer according to the design requirements to ensure that there are no bubbles and wrinkles. Then, according to the process requirements, it is given a pressure of 0.1 MPa and preliminarily cured at room temperature for 24 hours to ensure that the prepreg is tightly combined with the mold.

[0046] In this embodiment of the present invention, after the base layer is fully cured, it is placed in a mold. A 5mm thick layer of epoxy resin containing 20% ​​carbonyl iron by volume is evenly applied to the carbon fiber prepreg and cured. After the absorbing layer is fully cured, an ultrafast laser is used to precisely cut the cone shape into the carbonyl iron-epoxy resin, taking care to protect surrounding materials and structures from being affected by the laser processing.

[0047] In an embodiment of the present invention, after cutting, the epoxy resin is placed back into the mold. The epoxy resin and curing agent are precisely measured and mixed, stirred evenly, and all bubbles are removed using a vacuum pump. Once the mixture is free of bubbles, it is slowly poured into the mold, paying particular attention to covering the tapered area and ensuring that the epoxy resin fully penetrates and fills the entire space. A scraper or other tool is used to assist in spreading and filling the gaps.

[0048] In an embodiment of the present invention, after the filling layer is cured, a 0.1 mm thick quartz prepreg wave-transmitting skin is adhered to another layer of the filling layer using an epoxy adhesive film.

[0049] In an embodiment of the present invention, a metal sheet is cut according to design requirements and pre-treated (e.g., degreasing and rust removal). An ultrafast laser is used to cut the metal sheet into the desired circular cross shape. An adhesive is then used to firmly adhere or connect the metal sheet to the cured composite material structure. During this process, it is important to ensure that the bonding surface is clean, flat, and free of bubbles.

[0050] In an embodiment of the present invention, the sample size is 180 mm*180 mm. Figure 5 The figure is a comparison of the reflectivity of the pointed cone metamaterial composite absorbing structure and the traditional layer dielectric plate structure. The pointed cone metamaterial composite absorbing structure is an absorbing structure with an absorbing base thickness of 3.5mm and a cone thickness of 1.5mm, while the traditional layer dielectric plate has no cone or metamaterial structure. Figure 5 As shown in the figure, the pointed cone metamaterial composite absorbing structure can meet the average reflectivity of -5.13dB at 0.3~2GHz, which has a 2.5dB advantage over the average reflectivity of the traditional layer dielectric plate structure.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art may make various modifications or substitutions within the technical scope disclosed in the present invention, and all such modifications or substitutions shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A pointed cone metamaterial composite absorbing structure, characterized in that: The pointed cone metamaterial composite wave absorbing structure comprises a reflective layer (10), a wave absorbing array pointed cone structure (20), a wave-transmitting layer (30) and a metamaterial layer (40); The wave absorbing array pointed cone structure (20) comprises a cone structure (21) and a wave absorbing base (22); The wave-transmitting layer (30) comprises a filling structure layer (31) and a wave-transmitting skin (32); The reflective layer (10) is arranged below the wave absorbing base (22); The wave-transmitting skin (32) is arranged above the conical structure (21); The filling structure layer (31) is arranged in the gap between the conical structure (21) and the wave-transmitting skin (32); The metamaterial layer (40) is located above the wave-transmitting skin (32).

2. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The material of the reflective layer (10) is a carbon fiber composite material; The material of the wave absorbing array pointed cone structure (20) is carbonyl iron-epoxy resin; The material of the filling structure layer (31) is epoxy resin; The material of the wave-transmitting skin (32) is one of quartz prepreg and aramid prepreg; The material of the metamaterial layer (40) is a metal material.

3. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The cone structure (21) has a bottom radius of 3 to 5 mm and a height of 2 to 4 mm.

4. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The height of the wave absorbing base (22) is 1 to 3 mm.

5. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The pointed cones in the wave absorbing array pointed cone structure (20) are arranged in a horizontal and neat array.

6. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The thickness of the wave-transmitting skin (32) is 0.05-0.15 mm.

7. The pointed cone metamaterial composite absorbing structure according to claim 1, characterized in that: The thickness of the reflective layer (10) is 0.4-0.6 mm.

8. The pointed cone metamaterial composite wave absorbing structure according to claim 1, characterized in that: The metamaterial layer (40) has a thickness of 20 to 50 μm.

9. The pointed cone metamaterial composite wave absorbing structure according to claim 1, characterized in that: The structure of the metamaterial layer (40) is selected from at least one of a circular cross, a circular ring, and a square ring.

10. A method for preparing the tapered metamaterial composite wave absorbing structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: The carbon fiber prepreg is precisely laid on the bottom layer of the mold according to the design requirements to ensure that there are no bubbles and wrinkles. Then, according to the process requirements, a pressure of 0.1Mpa is applied and preliminary curing is carried out at room temperature for 24 hours to ensure that the prepreg is tightly bonded to the mold. After the base layer is fully cured, it is placed in a mold and a layer of carbonyl iron-epoxy resin is evenly applied to the carbon fiber prepreg and cured. After the carbonyl iron-epoxy resin layer is fully cured, ultrafast laser processing is used to precisely cut the cone shape on the carbonyl iron-epoxy resin, taking care to protect the surrounding materials and structures from being affected by the laser processing. After cutting, place it back into the mold; accurately measure and mix the epoxy resin and its curing agent, stir evenly, and use a vacuum pump to remove all bubbles; after there are no bubbles in the mixture, slowly pour it into the mold, paying special attention to covering the cone area and ensuring that the epoxy resin can fully penetrate and fill the entire space, and use tools such as scrapers to assist in spreading and filling gaps; After the epoxy resin is cured, the quartz prepreg wave-transparent skin is adhered to the other side of the epoxy resin layer using epoxy film; The metal sheet is cut and pre-processed according to the design requirements, and then cut into the required shape using an ultrafast laser. The metal sheet is then firmly adhered or connected to the cured composite material structure using an adhesive. During this process, it is necessary to ensure that the bonding surface is clean, flat, and free of bubbles, thereby obtaining the pointed cone metamaterial composite absorbing structure.

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