CN106684571A - Miura - Ori origami structure electromagnetic stealthl plate of loaded graphene metamaterial unit - Google Patents

Abstract

The present invention is a Miura-Ori origami structure electromagnetic cloaking board loaded with graphene metamaterial units. The preparation method of the electromagnetic cloaking board of the present invention is: immersing the substrate in a mixture of hydroquinone and graphene oxide, sealing and heat treatment , so that the substrate is attached with a wave-absorbing medium; after taking it out and cleaning it, freeze it and then dry it to obtain a graphene woven cloth; after dipping the graphene woven cloth in an epoxy resin precursor solution, lay it flat and heat and solidify it to obtain an electromagnetic stealth board; The electromagnetic cloaking board is creased according to the Miura-Ori origami method, so that the electromagnetic cloaking board stretches and deforms along the creases; and the above-mentioned metamaterial unit is glued on the surface of the electromagnetic cloaking board. Through the deformation design of the origami structure, the invention can change the incident angle and the electromagnetic wave propagation path to realize the frequency modulation stealth effect; through the matching of the metamaterial and the wave-absorbing matrix, a wider absorption efficiency can be effectively absorbed.

Description

Electromagnetic hiding of a Miura-Ori origami structure loaded with graphene metamaterial units body

technical field

The invention belongs to the field of design and preparation of frequency modulation stealth materials and structures, and in particular relates to a graphene/polymer new composite structure electromagnetic stealth board with adjustable frequency absorbing stealth performance.

Background technique

High-performance electromagnetic stealth materials (materials with strong absorption and weak reflection functions for electromagnetic waves) are in urgent demand in the fields of detection, communication, aerospace, aviation, and advanced equipment. Electromagnetic stealth technology uses electromagnetic stealth materials and structures to weaken, suppress, absorb, and deflect the intensity of electromagnetic waves to minimize the probability of (radar electromagnetic wave) detection system discovering and identifying (detecting targets). With the development of the information age, high-performance electromagnetic stealth materials have huge application potential and development space in many important fields of advanced equipment technology such as detection, target recognition, and electronic countermeasures. Design and develop "light, wide, thin, and strong" electromagnetic stealth materials It has become the research focus of science and technology circles and industrial circles. [R.C.Che, L.M.Peng, X.F.Duan, Q.Chen, X.Liang, Adv.Mater. Che, Adv. Mater. 2016, 28, 486.]

Conventional absorbing media include dielectric loss type, magnetic loss type, and magnetic-dielectric coupling loss type. Because it is easier to broaden the effective absorption in the low-frequency band, magnetic-dielectric coupling loss type absorbing media has always been concerned. Wang Jun et al. used Fe ₅₀ Ni ₅₀ modified reduced graphene oxide as a magnetic loss coupling absorber, and obtained an epoxy resin-based absorbing medium with an effective absorption bandwidth of 8.8-13.1 GHz [JOURNAL OF ALLOYS AND COMPOUNDS, Volume: 653 Pages: 14-21, 2015]. Recently, Che Renchao et al. have prepared CoNi@SiO ₂ @TiO ₂ and CoNi@Air@TiO ₂ multi-level microsphere structure absorbing dielectric fillers. The effective bandwidth can reach 8.1 GHz in the range of 2-18 GHz. The magnetoelectric coupling absorbing medium puts forward a new idea [QHLiu Q.Cao, H.Bi, CYLiang, KPYuan, W.She, YJYang, RCChe, Adv.Mater.2016, 28, 486].

Frequency-tunable stealth materials are a subversive means to solve the problem of narrow and prominent effective absorption bandwidth (frequency width of reflection loss value <-10dB) of stealth materials. [H.T.Chen, J.F.O'Hara, A.K.Azad, A.J.Taylor, R.D.Averitt, D.B.Shrekenhamer, and W.J.Padilla, Nat.Photonics 2, 295 (2008).; H.T.Chen, W.J.Padilla, J.M.O.Zide, A.C.Gossard, A.J.Taylor, and R.D.Averitt, Nature (London) 444,597 (2006)] Renchao Che et al. realized the movement of resonance absorption peaks in multiple frequency bands by adjusting the intrinsic physical parameters of stealth materials or changing the pattern structure of stealth metamaterials, and realized the function of responding to signals Frequency conversion, changing the response capability of the stealth structure to the frequency band of external target electromagnetic waves. Design a double-layer absorbing medium with a carbon nanotube array orientation angle. The effective absorption bandwidth is 7.2-8.6GHz (band width of reflection loss<-10dB) in the initial state (the angle is 0°). By changing the orientation angle Angle (0～90°), the best resonant peak frequency position moves from 7.9GHz to 11GHz, the effective absorbing bandwidth moves to 10～12.2GHz, and the adjustable absorbing bandwidth in the range of 7.2～12.2GHz is realized [Hao Sun , Renchao Che, Xiao You, Yishu Jiang, Zhibin Yang, Jue Deng, Longbin Qiu, and Huisheng Peng, Adv. Mater. 2014, 26, 8120–8125]. Therefore, compared with traditional stealth materials, frequency-tunable electromagnetic stealth materials have better absorbing bandwidth and flexibility under the same conditions, greatly reducing the thickness and weight of stealth materials, and enhancing the broadband response of stealth materials.

Due to the limitation of the thickness, it has been a research hotspot to realize the frequency modulation of the absorbing medium by adjusting the electromagnetic parameters in the absorbing medium to induce changes in the effective absorption resonance frequency and absorption strength.

(1) Frequency modulation of temperature field: Cao Maosheng et al. have studied dielectric materials with temperature response. The intrinsic polarization, electrical loss and magnetic loss of one-dimensional nano-cobalt chains will cause large changes in electromagnetic parameters with the increase of temperature. When the environment When the temperature changes from 50° to 300°, nano-cobalt chains/silica composites can achieve 8.2-11GHz tunable absorption bandwidth [Liu J, CaoMS.ACS Appl.Mater.Interfaces 2016,8,22615-22622].

(2) Polarization direction frequency modulation: Peng Huisheng et al. changed the polarization mode and propagation loss mode of electromagnetic waves by adjusting the interaction angle when the two-layer array fabric was stacked. By adjusting the interaction angle from 0 to 90 degrees, the absorption peak was achieved at 7.5- Controllable transformation in the 11GHz frequency range [Cross-Stacking Aligned Carbon-Nanotube Films to TuneMicrowave Absorption Frequencies and Increase Absorption Intensities. Adv. Mater. 2014, 26, 8120.].

In the frequency-tunable metamaterial absorbing material, Jiang Jianjun’s team designed a metamaterial stealth structure with an active frequency-selective surface containing PIN diodes. By adjusting the bias voltage in the structure to change the resonance characteristics, the optimal width stealth was achieved at 5.3-13GHz Performance [Chen Q, Jiang JJ, et al. Acta Phys. Sin. 2011, 60, 074202].

Although tunable stealth materials have made important progress recently, there are still two problems: (1) The tunable parameters are limited and the tunable frequency band is narrow. Currently implemented frequency modulation technology usually only regulates a single parameter within a limited range (in the range of several GHz), and the range of adjustable frequency bands that can be realized is narrow, and the realization of broadband frequency modulation is still facing challenges. (2) The theoretical model of the single adjustable dimension space (wave absorbing control dimension) needs to be improved. Most of the currently researched frequency-tunable methods rely on changing the physical performance parameters of materials in a single plane. There are still few experimental and theoretical studies on frequency modulation in multi-dimensional space based on structural deformation, and the understanding of the frequency modulation laws of metamaterial stealth structures in multi-dimensional space is still limited. .

Contents of the invention

The purpose of the present invention is to solve the problems of limited frequency modulation bandwidth range and mechanism and single frequency modulation dimension space, and provide a Miura-Ori origami structure electromagnetic stealth board loaded with graphene metamaterial units.

The purpose of the present invention is achieved through the following technical solutions:

A kind of electromagnetic stealth board of the present invention, specific preparation steps are as follows:

Step 1: Dissolve graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 1.0-9.0 mg/ml, add hydroquinone into the graphene oxide aqueous solution, and stir evenly; the mass ratio of hydroquinone to graphene oxide 0.1 to 10;

Step 2: immerse the substrate in the above mixture, and seal it; heat preservation treatment at 70-120°C for 2-20 hours, so that the substrate is attached with a wave-absorbing medium; the substrate is polymer fabric or polymer foam; Substrate thickness is 1~10mm;

Step 3: Take the substrate with the absorbing medium out of the mixture, soak it in water and wash it, spread it into a straight plate, freeze it at -20～-60℃ for 2～100 hours, and then dry it at room temperature for 2～ 100h, obtain graphene weaving;

Step 4: Mix epoxy resin and epoxy resin curing agent at a mass ratio of 1:1 to 1:3 to form an epoxy resin precursor solution; immerse the graphene woven fabric obtained in step 3 into the epoxy resin precursor Immerse in the body solution for more than 1 hour, take it out, pave it flat, heat and cure it at 70-150°C for 2-10 hours, and obtain an electromagnetic stealth board.

In order to improve the adjustable stealth performance of the electromagnetic cloaking board, the present invention also provides an electromagnetic cloaking board with a metamaterial unit structure, including the electromagnetic cloaking board prepared by the above method, and the metamaterial unit glued on the surface of the electromagnetic cloaking board , the metamaterial unit is a square, circular, cross-shaped, back-shaped sheet structure cut from the electromagnetic cloaking plate prepared by the above method, the outer length of the metamaterial unit is 5-40 mm, and the thickness of the metamaterial unit is the same as The thickness of the electromagnetic cloaking boards bonded is the same; all metamaterial units bonded on the same electromagnetic cloaking board have the same shape, and each metamaterial unit is distributed at equal intervals on the surface of the electromagnetic cloaking board.

In order to improve the adjustable stealth performance of the electromagnetic cloaking board, the present invention also provides a scalable and deformable electromagnetic cloaking board, and the electromagnetic cloaking board prepared by the above method is cut into a Miura-Ori origami method with an aspect ratio of 5:7 A rectangular plate, and then crease one side of the electromagnetic cloaking plate according to the Miura-Ori origami method, so that the electromagnetic cloaking plate stretches and deforms along the creases.

Further, the above-mentioned metamaterial units can be glued to the upper surface of the expandable and deformable electromagnetic cloaking plate, and the metamaterial units are distributed at equal intervals on the upper surface of the electromagnetic cloaking plate.

Beneficial effect

(1) Through the deformation design of the origami structure, the incident angle and the electromagnetic wave propagation path can be changed to achieve the FM stealth effect.

(2) The graphene-based fabric composite material is prepared by using the fabric as the matrix, and the graphene can be stably fixed in the three-dimensional fabric skeleton to form a deformable composite material.

(3) By matching the metamaterial and the absorbing matrix, multiple quarter-resonant peaks are matched and coupled to obtain effective absorption and wider absorption efficiency. Through the effect of coupling deformation, the flat state before deformation, the minimum reflection loss value is -10.2dB when tested at 8-18GHz; the stealth structure is deformed according to folding, and the minimum reflection loss value is -27.1dB when tested at 8-18GHz. 8-18GHz internal reflection loss value is lower than -10dB (lower than -10dB equals to the absorption of electromagnetic waves>90%, which can be approximately equal to the reduction of 90% of the volume of the object recognized on the radar, and the frequency band is 12.3-17.5GHz .

Description of drawings

Figure 1. Schematic diagram of the tiled Miura-Ori origami-structured electromagnetic cloaking plate loaded with graphene metamaterial units;

The reflection loss performance of Fig. 2 embodiment 1, the solid line is the flat state performance, and the dotted line is the folded state performance;

The reflection loss performance of Fig. 3 embodiment 2, the solid line is the flat state performance, and the dotted line is the folded state performance;

Figure 4 shows the reflection loss performance of Example 3, the solid line is the performance in the flat state, and the dotted line is the performance in the folded state.

detailed description

The content of the present invention will be further described below in conjunction with specific embodiments.

Example 1

Step 1: Dissolve graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 7.5 mg/ml, add hydroquinone to the graphene oxide aqueous solution, and stir evenly; the mass ratio of hydroquinone to graphene oxide is 5 ;

Step 2: Immerse the substrate in the above mixed solution, and seal it; heat preservation treatment at 100°C for 10 hours, so that the absorbing medium is attached to the substrate; the substrate is polymer fabric or polymer foam; the thickness of the substrate is 2mm ;

Step 3: Take the substrate with the absorbing medium out of the mixture, soak it in water and wash it, spread it into a straight plate, freeze it at -40°C for 10 hours, and dry it at room temperature for 48 hours to obtain a graphene woven fabric ;

Step 4: Mix epoxy resin and epoxy resin curing agent in a mass ratio of 1:3 to form an epoxy resin precursor solution; dip the graphene fabric obtained in step 3 into the epoxy resin precursor solution After 4 hours, take it out and pave it flat, heat and cure it at 120°C for 8 hours to obtain an electromagnetic stealth board.

Step 5: Cut the electromagnetic cloaking plate obtained in step 4 into a rectangular plate with an aspect ratio of 300×375mm conforming to the Miura-Ori origami method, and then process and fold one side of the electromagnetic cloaking plate according to the Miura-Ori origami method The side lengths of the parallelogram in the origami structure are 60.45mm and 51mm respectively, the long side and short side of the trapezoidal unit are 54mm and 51mm respectively, and the height is 60mm. The electromagnetic cloaking board is stretched and deformed along the crease. At the same time, cut the remaining part after cutting the rectangular plate into 140 square slices of 16×16mm;

Step 6: Glue the square sheets obtained in step 5 to the surface of the electromagnetic cloaking board obtained in step 5, and distribute the square sheets at equal intervals on the surface of the electromagnetic cloaking board to obtain a scalable load metamaterial unit. Deformable electromagnetic cloaking board.

The wave-absorbing performance test is carried out on the stretchable and deformable electromagnetic cloaking board loaded with metamaterial units obtained in the embodiment. The specific test conditions are: adopt the free space method, output the electromagnetic wave model to the battery cloaking board through a signal source of 8-18 GHz, and test the electromagnetic cloaking Reflection loss value (in dB) before and after plate deformation.

The test results are: in the flat state before deformation, the minimum reflection loss value of the test is -10.2dB; according to the folding deformation, the minimum reflection loss value is -27.1dB when tested at 8-18GHz, and the reflection loss value is lower than - The frequency band of 10dB is 12.3-17.5GHz.

Example 2

Step 1: dissolving graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 4 mg/ml, adding hydroquinone to the graphene oxide aqueous solution, and stirring evenly; the mass ratio of hydroquinone to graphene oxide is 2;

Step 2: Immerse the substrate in the above mixture, and seal it; heat preservation treatment at 120°C for 8 hours to attach the absorbing medium to the substrate; the substrate is polymer fabric or polymer foam; the thickness of the substrate is 2mm ;

Step 3: Take the substrate with the absorbing medium out of the mixture, soak it in water and wash it, spread it into a straight plate, freeze it at -40°C for 12 hours, and then dry it at room temperature for 36 hours to obtain a graphene woven fabric ;

Step 4: Mix epoxy resin and epoxy resin curing agent in a mass ratio of 1:3 to form an epoxy resin precursor solution; dip the graphene fabric obtained in step 3 into the epoxy resin precursor solution After 4 hours, take it out and pave it flat, heat and cure it at 100°C for 8 hours to obtain an electromagnetic stealth board.

Step 5: Cut the electromagnetic cloaking plate obtained in step 4 into a rectangular plate with an aspect ratio of 300×375mm conforming to the Miura-Ori origami method, and then process and fold one side of the electromagnetic cloaking plate according to the Miura-Ori origami method The side lengths of the parallelogram in the origami structure are 60.45mm and 51mm respectively, the long side and short side of the trapezoidal unit are 54mm and 51mm respectively, and the height is 60mm. The electromagnetic cloaking board is stretched and deformed along the crease. At the same time, cut the remaining part after cutting the rectangular plate into 140 square slices of 16×16mm;

Step 6: Glue the square sheets obtained in step 5 to the surface of the electromagnetic cloaking board obtained in step 5, and distribute the square sheets at equal intervals on the surface of the electromagnetic cloaking board to obtain a scalable load metamaterial unit. Deformable electromagnetic cloaking board.

The wave-absorbing performance test is carried out on the stretchable and deformable electromagnetic cloaking board loaded with metamaterial units obtained in the embodiment. The specific test conditions are: adopt the free space method, output the electromagnetic wave model to the battery cloaking board through a signal source of 8-18 GHz, and test the electromagnetic cloaking Reflection loss value (in dB) before and after plate deformation.

The test results are: in the flat state before deformation, the minimum reflection loss value of the test is -7.8dB; according to the folding deformation, the minimum reflection loss value is -17.1dB when tested at 8-18GHz, and the reflection loss value is lower than - The frequency band of 10dB is 13.9-17.4GHz.

Example 3

Step 1: Dissolving graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 2 mg/ml, adding hydroquinone to the graphene oxide aqueous solution, and stirring evenly; the mass ratio of hydroquinone to graphene oxide is 1;

Step 2: Immerse the substrate in the above mixture, and seal it; heat preservation treatment at 100°C for 8 hours, so that the absorbing medium is attached to the substrate; the substrate is polymer fabric or polymer foam; the thickness of the substrate is 2mm ;

Step 3: Take out the substrate attached with the absorbing medium from the mixture, soak it in water and wash it, spread it into a straight plate, freeze it at -40°C for 10 hours, and then dry it at room temperature for 30 hours to obtain a graphene woven fabric ;

Step 4: Mix epoxy resin and epoxy resin curing agent in a mass ratio of 1:3 to form an epoxy resin precursor solution; dip the graphene fabric obtained in step 3 into the epoxy resin precursor solution After 4 hours, take it out and pave it flat, heat and cure it at 110°C for 5 hours to obtain an electromagnetic stealth board.

Step 5: Cut the electromagnetic cloaking plate obtained in step 4 into a rectangular plate with an aspect ratio of 300×375mm conforming to the Miura-Ori origami method, and then process and fold one side of the electromagnetic cloaking plate according to the Miura-Ori origami method The side lengths of the parallelogram in the origami structure are 60.45mm and 51mm respectively, the long side and short side of the trapezoidal unit are 54mm and 51mm respectively, and the height is 60mm. The electromagnetic cloaking board is stretched and deformed along the crease. At the same time, cut the remaining part after cutting the rectangular plate into 140 square slices of 16×16mm;

Step 6: Glue the square sheets obtained in step 5 to the surface of the electromagnetic cloaking board obtained in step 5, and distribute the square sheets at equal intervals on the surface of the electromagnetic cloaking board to obtain a scalable load metamaterial unit. Deformable electromagnetic cloaking board.

The wave-absorbing performance test is carried out on the stretchable and deformable electromagnetic cloaking board loaded with metamaterial units obtained in the embodiment. The specific test conditions are: adopt the free space method, output the electromagnetic wave model to the battery cloaking board through a signal source of 8-18 GHz, and test the electromagnetic cloaking Reflection loss value (in dB) before and after plate deformation.

The test results are: in the flat state before deformation, the minimum reflection loss value of the test is -6.2dB; according to the folding deformation, the minimum reflection loss value is -13.6dB when tested at 8-18GHz, and the reflection loss value is lower than - The frequency band of 10dB is 14.3-18GHz.

Claims (6)

1. An electromagnetic stealth panel, characterized in that the specific preparation steps are as follows: Step 1: Dissolve graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 1.0-9.0 mg/ml, add hydroquinone into the graphene oxide aqueous solution, and stir evenly; the mass ratio of hydroquinone to graphene oxide 0.1 to 10; Step 2: immerse the substrate in the above mixture, and seal it; heat preservation treatment at 70-120°C for 2-20 hours, so that the substrate is attached with a wave-absorbing medium; the substrate is polymer fabric or polymer foam; Substrate thickness is 1~10mm; Step 3: Take the substrate with the absorbing medium out of the mixture, soak it in water and wash it, spread it into a straight plate, freeze it at -20～-60℃ for 2～100 hours, and then dry it at room temperature for 2～ 100h, obtain graphene weaving; Step 4: Mix epoxy resin and epoxy resin curing agent at a mass ratio of 1:1 to 1:3 to form an epoxy resin precursor solution; immerse the graphene woven fabric obtained in step 3 into the epoxy resin precursor Immerse in the body solution for more than 1 hour, take it out, pave it flat, heat and cure it at 70-150°C for 2-10 hours, and obtain an electromagnetic stealth board. 2. An electromagnetic cloaking board with a load metamaterial unit structure, characterized in that: comprising the electromagnetic cloaking board as claimed in claim 1, and a group of shapes glued on the top of the electromagnetic cloaking board as claimed in claim 1 The same and equidistantly distributed metamaterial units, the metamaterial unit is a sheet structure cut from the electromagnetic cloaking plate as claimed in claim 1, the outer length of the metamaterial unit is 5-40mm, and the thickness of the metamaterial unit is It is the same thickness as the glued electromagnetic stealth board. 3. An electromagnetic cloaking board loaded with a metamaterial unit structure as claimed in claim 2, characterized in that: the shape of the metamaterial unit is a square, circle, cross, or zigzag structure. 4. A scalable and deformable electromagnetic cloaking plate, characterized in that: the electromagnetic cloaking plate as claimed in claim 1 is cut into a rectangular plate with a length-to-width ratio of 5:7 meeting the Miura-Ori origami method, and then One side of the electromagnetic cloaking board is creased according to the Miura-Ori origami method, so that the processed electromagnetic cloaking board stretches and deforms along the creases. 5. A telescopically deformable electromagnetic cloaking plate of a load metamaterial unit structure, characterized in that: comprising the telescopically deformable electromagnetic cloaking plate as claimed in claim 4, and being bonded to the telescopically deformable electromagnetic cloaking plate as claimed in claim 4 A group of metamaterial units with the same shape and equally spaced distribution on the surface of the stretchable and deformable electromagnetic cloaking board, the metamaterial unit is a thin sheet structure cut by the electromagnetic cloaking board as claimed in claim 1, and the metamaterial unit The length of the outer side is 5-40mm, and the thickness of the metamaterial unit is the same as that of the electromagnetic cloaking plate to be glued. 6. A telescopically deformable electromagnetic cloaking board loaded with a metamaterial unit structure as claimed in claim 5, wherein the shape of the metamaterial unit is a square, a circle, a cross, or a back-shaped structure.