Electrically-controlled wave-absorbing composite material and preparation method thereof

Abstract

The invention discloses an electric control wave-absorbing composite material and a preparation method thereof, and belongs to the technical field of electromagnetic wave-absorbing materials. The electric control wave-absorbing composite material sequentially comprises a panel, an electric control metamaterial, a resistive film and a reflecting back plate from top to bottom, a core layer is arranged among the panel, the electric control metamaterial, the resistive film and the reflecting back plate; the resistive film comprises first structural units which are periodically arranged along x and y directions; the electric control metamaterial comprises second structure units which are periodically arranged in the x direction and the y direction and comprise PIN diodes, and the PIN diodes are embedded into the structure and integrally formed with the composite material. Therefore, the reliability of the electrically-controlled wave-absorbing material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic wave absorbing materials, and in particular relates to an electrically controlled wave absorbing composite material and a preparation method thereof. Background Art

[0002] Electromagnetic wave absorption refers to the dissipation and absorption of the energy of incident electromagnetic waves by using high-loss materials or strong resonant structures. Generally speaking, electromagnetic wave absorption must meet two basic conditions: one is to maximize the entry of incident waves into the material through impedance matching, and the other is to dissipate energy through good attenuation characteristics. Electromagnetic wave absorption technology achieves the improvement of radar performance and stealth performance of weapons and equipment by coating absorbents and absorbing structures.

[0003] Metamaterial structures are artificial structures with precisely adjustable electromagnetic properties composed of periodic or non-periodic arrangement of sub-wavelength-scale unit structures, which exhibit electromagnetic characteristics opposite to those of conventional materials. Compared with traditional electromagnetic absorbing materials, electromagnetic absorbing structures based on metamaterial technology have the advantages of low profile and excellent structural performance, and are widely used in the field of radar stealth. Since the working performance of passive electromagnetic absorbing structures is fixed once they are processed, relevant studies have proposed to load conductivity-adjustable materials in the absorbing structures to achieve dynamic reflectivity regulation. Compared with other adjustable absorbing materials, such as phase change materials, water-based or liquid metal-based adjustable materials, mechanically adjustable materials, etc., electrically controlled absorbing materials loaded with PIN diodes have the advantages of fast response speed and extremely high engineering application value. However, in current related studies, active devices are exposed to the outside, resulting in poor reliability of the structure and insufficient service life. In addition, related studies do not have stealth performance outside the adjustable frequency band. Summary of the invention

[0004] In view of the above problems, the present invention provides an electrically-controlled wave-absorbing composite material and a preparation method thereof, wherein a PIN diode is embedded in the structure and formed integrally with the composite structure, thereby improving the reliability of the electrically-controlled wave-absorbing material.

[0005] The first object of the present invention is to provide an electrically controlled wave absorbing composite material, which comprises, from top to bottom, a panel, an electrically controlled metamaterial, a resistor film and a reflective backplane; a core layer is provided between the panel, the electrically controlled metamaterial, the resistor film and the reflective backplane;

[0006] The resistive film includes first structural units periodically arranged along the x and y directions;

[0007] The electrically controlled metamaterial comprises a second structural unit containing PIN diodes which are periodically arranged along the x and y directions. The PIN diodes are embedded in the structure and formed integrally with the composite material.

[0008] In a preferred embodiment of the present invention, the second structural unit containing the PIN diode comprises a plurality of PIN diodes and a plurality of metallized meander lines welded in sequence.

[0009] In a preferred embodiment of the present invention, the second structural units containing PIN diodes are periodically arranged in a grid shape, the metallized meandering line serves as a negative electrode of the feeder, and the PIN diode serves as a positive electrode of the feeder.

[0010] In a preferred embodiment of the present invention, the square resistance of the resistor film is 65Ω / sq to 500Ω / sq; and the first structural unit is a square ring structural unit.

[0011] In a preferred embodiment of the present invention, the core layer is a wave-transmitting material.

[0012] In a preferred embodiment of the present invention, the core layer comprises:

[0013] A first core layer, which is disposed between the resistance film and the reflective back plate;

[0014] A second core layer, which is disposed between the electrically controlled metamaterial and the resistive film;

[0015] The third core layer is arranged between the electrically controlled metamaterial and the panel.

[0016] In a preferred embodiment of the present invention, the panel is a wave-transmitting composite material with a relative dielectric constant of 2.7 to 5.6, a dielectric loss angle of 0.15 to 0.025, and a thickness of 0.1 to 1.5 mm.

[0017] In a preferred embodiment of the present invention, the reflective back plate is made of conductive material.

[0018] The second object of the present invention is to provide a method for preparing the above-mentioned electrically controlled wave absorbing composite material, comprising the following steps:

[0019] The panel, electrically controlled metamaterial, resistive film, reflective backplane and core layer are laid out in sequence and then bonded, formed and cut to obtain the product.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In terms of structural performance, in the electrically controlled wave absorbing composite structure, the PIN diode is embedded in the structure and formed integrally with the composite structure. Since the feed network containing active devices is integrally embedded in the structure, it is protected, thereby improving the reliability of the electrically controlled wave absorbing material. In terms of electrical performance, the electrically controlled wave absorbing composite structure not only has excellent reflectivity dynamic control performance within the band, but also has broadband and strong absorption functions outside the band. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of an electrically controlled wave absorbing composite structure provided in an embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the resistor film in the electrically controlled wave-absorbing composite material provided in an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of the electrically controlled metamaterial in the electrically controlled wave absorbing composite structure provided in Example 1 of the present invention.

[0025] Figure 4 This is a simulated spectrum of the reflectivity of the electrically controlled wave absorbing composite structure when the resistance value RP of the PIN diode in Example 1 of the present invention changes and there is no resistance film.

[0026] Figure 5 It is a simulated spectrum of the reflectivity of the electrically controlled wave absorbing composite structure when the resistance value RP of the PIN diode in Example 1 of the present invention varies in the range of 3Ω to 203Ω.

[0027] Figure 6 It is a simulated spectrum of the reflectivity of the electrically controlled wave absorbing composite structure when the resistance value RP of the PIN diode in Example 1 of the present invention varies within the range of 253Ω to 1e+6Ω.

[0028] Figure 7 It is a simulated spectrum of the reflectivity of the electrically controlled wave absorbing composite structure when the resistance value RP of the PIN diode in Example 1 of the present invention is equal to 3Ω and the square resistance SR of the resistor film varies in the range of 85Ω / sq to 285Ω / sq.

[0029] Figure 8 This is a simulated spectrum of the reflectivity of the electrically controlled wave absorbing composite structure when the PIN diode resistance RP is equal to 1e+6Ω and the square resistance SR of the resistor film varies in the range of 85Ω / sq to 285Ω / sq in Example 1 of the present invention.

[0030] Fig. 9 Spectra of reflectivity test of the electrically controlled wave absorbing composite structure under different bias voltages in Example 1 of the present invention.

[0031] Reference numerals:

[0032] 1-resistance film, 2-electrically controlled metamaterial, 3-reflection backplane, 4-first core layer, 5-second core layer, 6-third core layer, 7-panel, 11-first structural unit, 22-second structural unit, h 1 -Thickness of the first core layer, h 2 -Thickness of the second core layer, h 3 -Thickness of the third core layer, p 1 - first structural unit period, l 1-Outer length, g 1 -Inner side length, p 2 - the period of the second structural unit, l 2 - Length of stub, g 2 -Stub spacing, g 22 -PIN diode soldering area clearance, l 22 - PIN diode soldering area length, d 22 -PIN diode welding area width, w 2 -Stub width. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0034] As described in the background technology, in current related research, active devices are exposed to the outside, which often leads to poor reliability of the composite structure and insufficient service life. In addition, related research does not have stealth performance outside the adjustable frequency band. In response to these problems, the present invention combines the electrically controlled metamaterial 2 and the resistive film 1 to achieve integrated design, preparation and complementary advantages of the two, thereby solving the above technical problems. The specific technical solution is as follows:

[0035] An electrically controlled wave absorbing composite material, comprising, from top to bottom, a panel 7, an electrically controlled metamaterial 2, a resistor film 1 and a reflective backplane 3; a core layer is provided between the panel 7, the electrically controlled metamaterial 2, the resistor film 1 and the reflective backplane 3;

[0036] The resistance film 1 comprises first structural units 11 periodically arranged along the x and y directions;

[0037] It is understood that the present invention does not limit the type of the first structural unit 11, for example, square, circular, and annular shapes are all applicable. The spacing between the first structural units 11 can be freely adjusted according to the size of their period.

[0038] The electrically controlled metamaterial 2 comprises a second structural unit 22 containing PIN diodes which are periodically arranged along the x and y directions. The PIN diodes are embedded in the structure and formed integrally with the composite material.

[0039] In the electrically controlled absorbing composite material provided by the present invention, the panel 7 is arranged at the top of the structure as a skin to improve the mechanical strength of the electrically controlled absorbing composite material. The electrically controlled metamaterial 2 dynamically adjusts the equivalent impedance at low frequency and transmits waves at high frequency. The resistor film 1 transmits waves at low frequency and loses electromagnetic waves at high frequency. The reflective backplane 3 is arranged at the bottom of the electrically controlled absorbing composite material to provide an electrical boundary. The core layer is arranged in the middle of the structure as a core material to protect the active devices in the electrically controlled metamaterial 2 and as a dielectric layer of the electromagnetic structure.

[0040] In a preferred embodiment, the second structural unit 22 containing a PIN diode comprises a PIN diode and a metallized meander line welded in sequence;

[0041] The second structural units 22 containing PIN diodes are arranged periodically in a grid shape, the metallized meandering line serves as a negative electrode of the feeder, and the PIN diode serves as a positive electrode of the feeder.

[0042] The electrically controlled metamaterial described in the present invention is prepared by a PCB process. The present invention has no particular limitation on the substrate in the electrically controlled metamaterial 2. Any circuit board microwave plate familiar to those skilled in the art can be used as the substrate. Those skilled in the art can select and adjust it according to actual application conditions, product quality and product performance. Preferably, the thickness is 0.08-0.3 mm.

[0043] It can be understood that in order to simplify the preparation process of the electrically controlled absorbing composite structure, the electrically controlled metamaterial 2 adopts a series feeder method, and metal patterns are respectively etched on the front and back sides of the substrate. The reflectivity of the electrically controlled absorbing composite material can be independently adjusted under different polarizations. Specifically, the present invention provides that the reflectivity of the electrically controlled absorbing composite material can be independently adjusted under different polarizations by adjusting the external bias voltage.

[0044] In a preferred embodiment, the square resistance of the resistor film 1 is 65Ω / sq-500Ω / sq; and the first structural unit 11 is a square ring structural unit.

[0045] It can be understood that the resistor film 1 is prepared by screen printing process, and the substrate is a wave-transmitting film.

[0046] In a preferred embodiment, the core layer is a wave-transmitting material. Specifically, the core layer is a lightweight wave-transmitting material such as foam or aramid honeycomb.

[0047] The core layer comprises:

[0048] The first core layer 4 is provided between the resistor film 1 and the reflective back plate 3; the thickness of the first core layer 4 is h 1 4.8±1.5mm;

[0049] The second core layer 5 is provided between the electrically controlled metamaterial 2 and the resistor film 1; the thickness of the second core layer 5 is h 2 14.2±1.5mm;

[0050] The third core layer 6 is provided between the electrically controlled metamaterial 2 and the panel 7. The thickness of the third core layer 6 is h 3 3±1.5mm.

[0051] The present invention has no particular limitation on the thickness of the first core layer 4 , the second core layer 5 and the third core layer 6 , and the thickness of the core material may vary under different structural periods.

[0052] It can be understood that the present invention has no special restrictions on the panel 7. Those skilled in the art can select and adjust the panel 7 according to actual application conditions, product quality and product performance. In a preferred embodiment, the panel 7 is a wave-transmitting composite material with a relative dielectric constant of 2.7 to 5.6, a dielectric loss angle of 0.15 to 0.025, and a thickness of 0.4 to 1 mm.

[0053] Specifically, the wave-transmitting composite material is a wave-transmitting fiber reinforced resin-based composite material, wherein the wave-transmitting fiber is glass fiber, quartz fiber, etc. The dielectric constant and loss angle of the quartz fiber reinforced epoxy resin-based composite material are 3.5 and 0.006 respectively; the dielectric constant and loss angle of the glass fiber reinforced epoxy resin-based composite material are 4.1 and 0.02 respectively.

[0054] It can be understood that the present invention has no special limitation on the reflective backboard 3. Those skilled in the art can select and adjust the reflective backboard 3 according to actual application conditions, product quality and product performance. In a preferred embodiment, the reflective backboard 3 is a conductive material with a thickness of 0.4 to 1 mm.

[0055] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0056] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0057] Unless otherwise specified, the methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0058] The technical solution of the present invention is further described below by taking specific embodiments as examples.

[0059] Example 1

[0060] This embodiment provides an electrically controlled wave absorbing composite material, specifically a foam-based sandwich composite material, such as Figure 1 As shown, from top to bottom, it includes a panel 7, a third core layer 6, an electrically controlled metamaterial 2, a second core layer 5, a resistor film 1, a first core layer 4 and a reflective backplane 3;

[0061] In this embodiment, the thickness of the third core layer 6 is h 3 is 3 mm, and the thickness of the second core layer 5 is h 2 is 14.2 mm, and the thickness of the first core layer 4 is h 1 The thickness of the first core layer 4, the second core layer 5 and the third core layer 6 are foam core layers. The dielectric constant and loss angle of the first core layer 4, the second core layer 5 and the third core layer 6 are in the range of 1.02 to 1.05 and 0.002 to 0.008 respectively.

[0062] Panel 7 is a quartz fiber panel; the relative dielectric constant of the panel is 3.5, the dielectric loss angle is 0.006, and the thickness is 0.4 mm;

[0063] The reflective back plate 3 is a carbon fiber back plate, and the relative dielectric constant of the reflective back plate 3 is 0.006 and the thickness is 0.4 mm.

[0064] like Figure 2 As shown, in this embodiment, the resistor film 1 is a first structural unit 11 arranged periodically in a square ring shape, and the first structural unit 11 has a period p 1 17.8mm, outer length l 1 14.6mm, inner side length g 1 is 6.9 mm. That is, the spacing between adjacent first structural units 11 is p 1 -l 1 In the preparation process, a conductive paste is used to prepare a resistor film by screen printing, and the square resistance of the resistor film is within 65Ω / sq to 500Ω / sq. In this embodiment, the square resistance of the resistor film layer is 85Ω / sq. The printed substrate of the resistor film is a FR-4 dielectric sheet with a thickness of 0.1mm, a relative dielectric constant of 4.1, and a dielectric loss angle of 0.025.

[0065] like Figure 3 As shown, in this embodiment, the electrically controlled metamaterial 2 includes a second structural unit 22. The second structural unit 22 includes two parts: a metallized meander line and a PIN diode.

[0066] The metallized meander line includes multiple short stub segments, and the short stub width w2 0.15mm, the stub length l 2 0.65mm, stub spacing g 2 0.15mm, metallized meander length l t The calculation formula is as follows:

[0067] l t =(w 2 *2+g 2 *2)*n*2+w 2 .

[0068] Where n is the number of stubs contained in the meander line.

[0069] In this embodiment, the length of the metallized meander line unit is 4.65 mm. It should be noted that the material used for the metallized curve in the present invention is copper.

[0070] PIN diode welding area length l 22 The width of the PIN diode welding area is 2.1 mm. 22 0.5mm, PIN diode welding area gap g 22 The area of ​​the PIN-diode welding area is much larger than the physical size of the PIN-diode to reduce the influence of the PIN-diode displacement on the adjustable performance. In this embodiment, the second structural unit 22 of the electrically controlled metamaterial 2 is composed of three metallized meander lines and three PIN diodes, with a period p 2 It is 17.85mm.

[0071] In this embodiment, the electrically controlled metamaterial 2 in the electrically controlled wave absorbing composite structure is a 17×17 unit array with a total size of 303.45 mm×303.45 mm. Figure 2 As shown, at both ends of the electrically controlled metamaterial 2, a PIN diode and a metallized meander line serve as the positive and negative electrodes of the feeder, respectively;

[0072] The electrically controlled metamaterial 2 is prepared by PCB technology, using FR-4 copper clad board as the material, with a copper thickness of 0.017 mm, a dielectric thickness of 0.1 mm, a relative dielectric constant of 4.1, and a dielectric loss angle of 0.025. In order to obtain polarization-independent characteristics, the electrically controlled metamaterial 2 is etched on the front and back of the copper clad board, and the direction of the meander line (feed line) in the metal array is consistent with the polarization direction of the electric field.

[0073] During preparation, the panel 7, the third core layer 6, the electrically controlled metamaterial 2, the second core layer 5, the resistor film 1, the first core layer 4 and the reflective backplane 3 are laid in order, then bonded with an adhesive, and processed using a hand lay-up process. After processing, the surface is cut to 330 mm × 330 mm.

[0074] In this embodiment, a single PIN-diode is turned on under the conditions of voltage of 0.89V and current of 4mA, and the electrically controlled wave absorbing composite structure is turned on under the conditions of voltage of 44V and current of 68mA. In the simulation process, the resistance value R of the PIN-diode in the conducting and non-conducting states is P They are equivalent to 1e+6Ω and 3Ω respectively; in the diode adjustment state, the resistance value of the PIN-diode is adjusted within the range of 3Ω to 1e+6Ω.

[0075] like Figure 4 As shown, when there is no resistance film layer 1 in the electrically controlled wave absorbing composite structure, when the PIN-diode equivalent resistance R P From 3Ω to 1e+6Ω, within 2-6GHz, the simulated reflection first becomes smaller and then becomes larger; when R P When it is equal to 253Ω, the reflectivity reaches the minimum value, which is the optimal absorbing performance.

[0076] like Figure 5 As shown, when the PIN-diode is in the on state, its equivalent resistance R P =3Ω, the electrically controlled metamaterial 2 in the electrically controlled wave absorbing composite structure is almost transparent to electromagnetic waves within 2-6GHz, but due to the loss effect of the resistor film 1, its simulated reflectivity gradually decreases as the spectrum increases. P Changing from 3Ω to 203Ω, within 2-6GHz, the simulated reflectivity gradually decreases, and the electrically controlled wave absorbing composite structure gradually changes from a reflective state to an absorbing state. At the same time, due to the loss effect of the resistor film 1, within 6-18GHz, the simulated reflectivity of the electrically controlled wave absorbing composite structure is less than -10dB; within 6-14GHz, the simulated reflectivity is less than -15dB.

[0077] like Figure 6 As shown, when the PIN-diode is in the off state, its equivalent resistance R P =1e+6Ω, the electrically controlled metamaterial 2 in the electrically controlled wave absorbing composite structure almost reflects electromagnetic waves within 2-6GHz, and the simulated reflectivity of the electrically controlled wave absorbing composite structure is greater than -1dB. P From 253Ω to 1e+6Ω, the simulated reflectivity gradually decreases within 2-6GHz, and the electrically controlled absorbing composite structure gradually changes from the absorbing state to the reflecting state. At the same time, due to the loss effect of the resistor film 1, the simulated reflectivity of the electrically controlled absorbing composite structure is less than -10dB within 6-18GHz; within 6-14GHz, the simulated reflectivity is less than -15dB.

[0078] like Figure 7 As shown, when the PIN-diode is in the on state, its equivalent resistance R P=3Ω, the electrically controlled metamaterial 2 in the electrically controlled wave absorbing composite structure is almost transparent to electromagnetic waves within 2-6GHz, but due to the loss effect of the resistor film 1, its reflectivity gradually decreases as the spectrum increases. When the square resistance SR of the resistor film 1 changes from 85Ω / sq to 285Ω / sq, the simulated reflectivity within 8-18GHz gradually decreases, and this change does not affect the reflectivity within 2-6GHz.

[0079] like Figure 8 As shown, when the PIN-diode is in the off state, its equivalent resistance R P =1e+6Ω, the electrically controlled metamaterial 2 in the electrically controlled wave absorbing composite structure almost reflects electromagnetic waves within 2-6GHz, and the simulated reflectivity of the electrically controlled wave absorbing composite structure is greater than -1dB. When the square resistance SR of the resistor film 1 changes from 85Ω / sq to 285Ω / sq, the simulated reflectivity gradually decreases within 8-18GHz, and this change does not affect the reflectivity within 2-6GHz.

[0080] The electrically controlled wave absorbing composite structure is tested in a dark room using a free space method. Fig. 9 As shown, when the external bias voltage is adjusted from 0V to 43.8V, within 2-6GHz, the test reflectivity of the electrically controlled absorbing composite structure changes from -2dB to -20dB, and the regulation depth is greater than 15dB; when the external bias voltage is equal to 28.8V, the reflectivity reaches the minimum value, that is, the optimal absorbing performance. Within 6-18GHz, the test reflectivity of the electrically controlled absorbing composite structure is lower than -8dB; within 6-14GHz, the test reflectivity is less than -15dB. The electrically controlled absorbing composite structure does not affect the absorbing performance within the non-adjustable 6-18GHz during the reflectivity regulation process.

[0081] Example 2

[0082] This embodiment provides an electrically controlled wave absorbing composite material, specifically a foam-based sandwich composite material, such as Figure 1 As shown, from top to bottom, it includes a panel 7, a third core layer 6, an electrically controlled metamaterial 2, a second core layer 5, a resistor film 1, a first core layer 4 and a reflective backplane 3;

[0083] In this embodiment, the thickness of the third core layer 6 is h 3 is 4.5 mm, and the thickness of the second core layer 5 is h 2 is 12.7 mm, and the thickness of the first core layer 4 is h 1 The thickness of the first core layer 4, the second core layer 5 and the third core layer 6 are foam core layers. The dielectric constant and loss angle of the first core layer 4, the second core layer 5 and the third core layer 6 are in the range of 1.02 to 1.05 and 0.002 to 0.008 respectively.

[0084] Panel 7 is a quartz fiber panel; the relative dielectric constant of the panel is 3.5, the dielectric loss angle is 0.006, and the thickness is 1 mm;

[0085] The reflective back plate 3 is a carbon fiber back plate, and the relative dielectric constant of the reflective back plate 3 is 0.006 and the thickness is 1 mm.

[0086] In this embodiment, the resistor film 1 is a first structural unit 11 arranged periodically in a square ring shape. The first structural unit 11 has a period p 1 17.8mm, outer length l 1 14.6mm, inner side length g 1 is 6.9 mm. That is, the spacing between adjacent first structural units 11 is p 1 -l 1 In the preparation process, a conductive paste is used to prepare a resistor film 1 by screen printing. In this embodiment, the square resistance of the resistor film layer is 55Ω / sq. The printed substrate of the resistor film is a FR-4 dielectric sheet with a thickness of 0.1mm, a relative dielectric constant of 4.1, and a dielectric loss angle of 0.025.

[0087] Example 3

[0088] This embodiment provides an electrically controlled wave absorbing composite material, specifically a foam-based sandwich composite material, such as Figure 1 As shown, from top to bottom, it includes a panel 7, a third core layer 6, an electrically controlled metamaterial 2, a second core layer 5, a resistor film 1, a first core layer 4 and a reflective backplane 3;

[0089] In this embodiment, the thickness of the third core layer 6 is h 3 is 1.5 mm, and the thickness of the second core layer 5 is h 2 is 15.7 mm, and the thickness of the first core layer 4 is h 1 The thickness of the first core layer 4, the second core layer 5 and the third core layer 6 are foam core layers. The dielectric constant and loss angle of the first core layer 4, the second core layer 5 and the third core layer 6 are in the range of 1.02 to 1.05 and 0.002 to 0.008 respectively.

[0090] Panel 7 is a quartz fiber panel; the relative dielectric constant of the panel is 3.5, the dielectric loss angle is 0.006, and the thickness is 0.8 mm;

[0091] The reflective back plate 3 is a carbon fiber back plate, and the relative dielectric constant of the reflective back plate 3 is 0.006 and the thickness is 0.8 mm.

[0092] In this embodiment, the resistor film 1 is a first structural unit 11 arranged in a circular periodic manner. The first structural unit 11 has an outer diameter of 15 mm and an inner diameter of 7 mm. That is, the spacing between adjacent first structural units 11 is 3 mm. In the preparation process, a conductive paste is used to prepare the resistor film 1 by screen printing. In this embodiment, the square resistance of the resistor film layer is 250Ω / sq. The printed substrate of the resistor film is a FR-4 dielectric sheet with a thickness of 0.1 mm, a relative dielectric constant of 4.1, and a dielectric loss angle of 0.025.

[0093] It should be noted that the material of the structure in the present invention is only one of the embodiments of the present invention, and the specific selection is determined according to the actual situation, and the present invention does not limit this. It should be noted that the above structural dimensions are only one of the embodiments, for illustrative purposes, and the specific size changes are determined according to the actual situation, and the present invention does not limit this.

[0094] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0095] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An electrically controlled wave-absorbing composite material, characterized in that: The device comprises, from top to bottom, a panel (7), an electrically controlled metamaterial (2), a resistor film (1) and a reflective backplane (3); a core layer is provided between the panel (7), the electrically controlled metamaterial (2), the resistor film (1) and the reflective backplane (3); The resistance film (1) comprises first structural units (11) arranged periodically along the x and y directions; The electrically controlled metamaterial (2) comprises a second structural unit (22) containing PIN diodes which are periodically arranged along the x and y directions, and the PIN diodes are embedded in the structure and formed integrally with the composite material.

2. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The second structural unit (22) containing PIN diodes comprises a plurality of PIN diodes and a plurality of metallized meander lines welded in sequence.

3. The electrically controlled wave absorbing composite material according to claim 2, characterized in that: The second structural units (22) containing PIN diodes are arranged periodically in a grid shape, the metallized meandering line serves as a negative electrode of the feeder, and the PIN diode serves as a positive electrode of the feeder.

4. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The square resistance of the resistor film (1) is 65Ω / sq to 500Ω / sq; and the first structural unit (11) is a square ring-shaped structural unit.

5. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The core layer is made of wave-transmitting material.

6. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The core layer comprises: A first core layer (4) disposed between the resistor film (1) and the reflective back plate (3); A second core layer (5) is provided between the electrically controlled metamaterial (2) and the resistive film (1); A third core layer (6) is arranged between the electrically controlled metamaterial (2) and the panel (7).

7. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The panel (7) is a wave-transmitting composite material with a relative dielectric constant of 2.7 to 5.6, a dielectric loss angle of 0.15 to 0.025, and a thickness of 0.1 to 1.5 mm.

8. The electrically controlled wave absorbing composite material according to claim 1, characterized in that: The reflective back plate is made of conductive material.

9. A method for preparing the electrically controlled wave absorbing composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The panel (7), the electrically controlled metamaterial (2), the resistor film (1), the reflective backplane (3) and the core layer are laid in sequence, and then bonded, formed and cut to obtain the product.

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