A graphene-based flexible electro-reconfigurable wave-absorbing surface and preparation method thereof

Abstract

The present invention discloses a graphene-based flexible electrically reconfigurable absorbing surface and a preparation method thereof. The absorbing surface comprises a first PET substrate (11), a first graphene layer (21), a second graphene layer (22), a second PET substrate (12), a first PDMS dielectric layer (3), a third PET substrate (41), a first graphene strip (51), a second graphene strip (52), a fourth PET substrate (42), a patterned multilayer graphene square array (6), a second PDMS dielectric layer (7), and a multilayer graphene backplane (8) which are stacked from top to bottom. Based on the electrically induced square resistance adjustable characteristic of graphene, the present invention realizes a flexible reconfigurable absorbing surface. The specific functions include perfect absorption of incident waves, and the resonant frequency and the resonant amplitude can be independently adjusted, paving the way for the flexible application of graphene in electromagnetic stealth, deception, etc. in the microwave band.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave devices and relates to a graphene-based flexible electrically reconfigurable wave-absorbing surface and a preparation method thereof. Background Art

[0002] Reconfigurable flexible microwave absorbing surfaces are in great demand in stealth technology and electromagnetic deception, and can be used to hide complex targets such as aircraft and drones. Traditional reconfigurable absorbing surfaces usually use semiconductor devices such as varactor diodes, integrated resistors, etc. to achieve dynamic reconfiguration of frequency and / or amplitude (X.Wu, C.Hu, Y.Wang, M.Pu, C.Huang, C.Wang, and X.Luo, "Active microwave absorber with the dual-ability ofdividablemodulation in absorbing intensity and frequency," AIP Adv.vol.3,no.2,2013). However, despite the complex feeding network and complex manufacturing process, this method still has difficulty integrating traditional rigid components with flexible dielectric substrates. Therefore, it is still a huge challenge to realize absorbing surfaces with integrated reconfigurable and flexible functions.

[0003] As an emerging two-dimensional planar material, graphene has shown outstanding properties in mechanics, electricity, optics, biochemistry, etc. For example, a single-layer graphene has a transmittance of nearly 97.7% and the fastest electron mobility (15000cm 2 / v / cm), ultra-high charge carrier mobility (200000cm) that is not temperature-controlled 2 / v / s) and an efficient Fermi velocity close to the speed of light (10 6 m / s). Graphene also has excellent mechanical properties, with a Young's modulus of 1.0TPa. In addition, it has excellent electronic conductivity and flexibility.

[0004] It is precisely because of these properties of graphene that a large number of scientific researchers have paid great attention to it. After more than a decade of development, many researchers have used graphene to absorb and control electromagnetic waves (Osman Balci, Emre O. Polat, Nurbek Kakenov and Coskun Kocabas. "Graphene-enabled electrically switchable radar-absorbing surfaces," Nat. Commun. 2015). However, these works are mainly theoretical, and most of them are in the terahertz frequency band. In the microwave band commonly used in current communication technology, there is little work on using graphene for dynamic tuning. The reason is that the characteristics of graphene in the microwave band are equivalent to a layer of adjustable resistor film, and the imaginary part of its impedance is very small. Therefore, graphene needs to be patterned to obtain the "equivalent imaginary part" (MY Geng, ZG Liu, WJ Wu, H. Chen, B. Wu, and WB Lu, "A Dynamically Tunable Microwave Absorber Based on Graphene," IEEE Trans. Antennas Propag., vol. 68, no. 6, 2020). In recent years, researchers have used graphene and semiconductor devices such as varactor diodes and integrated resistors to achieve dynamic reconfiguration of frequency and amplitude (J. Zhang, XZ Wei, ID Rukhlenko, HTChen, and WR Zhu, "Electrically Tunable Metasurface with Independent Frequency and Amplitude Modulations," ACS Photonics, vol. 7, no. 1, 2020). In this hybrid structure, graphene is used as the amplitude adjustment layer, and the frequency is tuned by controlling semiconductor devices (PIN tubes, varactor diodes). However, this type of hybrid structure requires the design of a complex feeding network to provide electrical excitation signals for components such as varactor diodes and PIN diodes, which is a challenging task; at the same time, this type of tunable absorbing surface containing active semiconductor devices is bulky and cannot be planarized, so it is difficult to conform to the curved surface carrier in actual engineering applications.

[0005] Although research on microwave absorbing surfaces has progressed rapidly, it is still very challenging to achieve structural flexibility and dual tuning of resonant frequency and amplitude in one structure. If the absorbing surface can be made independently frequency and amplitude dynamically reconfigurable and structurally flexible and bendable, it can be compatible with flexible platforms and can be applied to curved surfaces, giving the design of the absorbing surface a higher degree of freedom. Summary of the invention

[0006] Technical title: The technical problem to be solved by the present invention is to use graphene to realize the flexible electro-reconfigurable absorbing surface in the microwave band, including dynamic reconfiguration of the resonant frequency and the resonant amplitude. The present invention proposes a flexible electro-reconfigurable absorbing surface based on graphene, including a graphene capacitor, a PDMS dielectric layer, a patterned graphene capacitor, a multi-layer graphene square array, a PDMS dielectric layer and a multi-layer graphene backplane stacked from top to bottom; each layer structure constituting the absorbing surface structure of the present invention is flexible and bendable, realizing the overall flexibility of the absorbing surface.

[0007] Technical solution: A graphene-based flexible electro-reconfigurable wave-absorbing surface of the present invention comprises a first PET substrate, a first graphene layer, a second graphene layer, a second PET substrate, a first PDMS dielectric layer, a third PET substrate, a first graphene strip, a second graphene strip, a fourth PET substrate, a patterned multilayer graphene square array, a second PDMS dielectric layer, and a multilayer graphene backplane stacked from top to bottom;

[0008] The graphene capacitor is composed of a first PET substrate, a first graphene layer arranged on the first PET substrate, a second PET substrate, a second graphene layer arranged on the second PET substrate, and a capacitor diaphragm paper soaked in an ionic liquid filled between the first PET substrate and the second PET substrate; the first PET substrate and the second PET substrate are overlapped, and the first graphene layer and the second graphene layer are respectively arranged on the inner surfaces of the first PET substrate and the second PET substrate;

[0009] A patterned graphene capacitor is formed by a third PET substrate, a first graphene strip arranged on the third PET substrate, a fourth PET substrate, a second graphene strip arranged on the fourth PET substrate, and a capacitor diaphragm paper impregnated with ionic liquid filled between the third PET substrate and the fourth PET substrate; the third PET substrate and the fourth PET substrate are overlapped, and the first graphene strip and the second graphene strip are respectively arranged on the inner surfaces of the first PET substrate and the second PET substrate.

[0010] The first graphene layer and the second graphene layer have complete structures and are not patterned;

[0011] The first graphene strip and the second graphene strip both include graphene strip units that are periodically arranged at equal intervals to form a graphene strip array; the graphene strip units are rectangular, and the graphene strip units on the first graphene strip correspond to the graphene strip units on the second graphene strip one by one.

[0012] The thickness of the capacitor diaphragm paper soaked with the ionic liquid filled between the first PET substrate and the second PET substrate is 50-100 microns.

[0013] The thickness of the capacitor diaphragm paper soaked with the ionic liquid filled between the third PET substrate and the fourth PET substrate is 50-100 microns.

[0014] The patterned multilayer graphene square array comprises a periodically arranged multilayer graphene square unit array, wherein the multilayer graphene square units are parallel to the first graphene strips and the second graphene strips.

[0015] The size of the first graphene strip and the second graphene strip unit is a rectangle of 5.0mm*6.0mm, and the interval between the graphene strip units is 1.0mm.

[0016] The unit size of the patterned multilayer graphene square array is 4.2 mm*4.2 mm.

[0017] The method for preparing the graphene-based flexible electro-reconfigurable wave-absorbing surface comprises the following steps:

[0018] Step 1, using Matlab and equivalent circuit theory to model the graphene capacitor, the first PDMS dielectric layer, the patterned graphene capacitor, the patterned graphene square array, the second PDMS dielectric layer and the multilayer graphene backplane, and optimizing the graphene strip unit size, graphene strip unit spacing, graphene square resistance, and the size of the multilayer graphene square unit with the best reconfigurable function through parameter scanning;

[0019] Etching the graphene on the third PET substrate and the fourth PET substrate by laser to obtain a first graphene strip array attached to the third PET substrate and a second graphene strip array attached to the fourth PET substrate;

[0020] Step 3, filling capacitor diaphragm paper soaked in ionic liquid between the first PET substrate and the second PET substrate to form a graphene capacitor;

[0021] Step 4, filling capacitor diaphragm paper soaked in ionic liquid between the third PET substrate and the fourth PET substrate to form a patterned graphene capacitor;

[0022] Step 5, attaching a patterned multilayer graphene square array and a multilayer graphene backplane to the upper and lower surfaces of the second PDMS dielectric layer respectively;

[0023] Step 6, the graphene capacitor, the first PDMS layer, the patterned graphene capacitor, the patterned graphene square array, the second PDMS dielectric layer, and the multilayer graphene backplane prepared above are sequentially bonded from top to bottom to form a flexible reconfigurable electro-absorbent surface structure.

[0024] In step 1, MATLAB and equivalent circuit theory are used to model the graphene capacitor, the first PDMS dielectric layer, the patterned graphene capacitor, the patterned graphene square array, the second PDMS dielectric layer and the multilayer graphene backplane; when the incident electromagnetic wave is incident vertically, the unpatterned graphene is equivalent to a resistor; the graphene strip array is equivalent to a series connection of a resistor, a capacitor and an inductor; the patterned graphene square array is equivalent to a capacitor; the first PET substrate, the second PET substrate, the first PDMS dielectric layer, the second PDMS dielectric layer, and the multilayer graphene backplane are characterized by their respective standard transmission line models.

[0025] Beneficial effects: The present invention provides a graphene-based flexible electrically reconfigurable absorbing surface structure, which relies on laser etching of large-area graphene strip array technology and combines the composite structure of patterned graphene capacitors and unpatterned graphene capacitors. It proves from theory to experiment that graphene can perform dual tuning of frequency and amplitude of the absorbing surface in the microwave band, thereby realizing the dynamic reconfiguration of the absorbing structure, laying a solid foundation for the large-scale application of graphene in the microwave band. At the same time, the various layers of structure that make up the absorbing surface in the present invention are flexible and bendable, providing a new idea for the application of graphene in actual electromagnetic protection scenarios in the microwave band.

[0026] The graphene-based flexible electro-reconfigurable absorbing surface of the present invention has a simple structure. The square resistance of graphene can be controlled by applying different voltages to it through a DC voltage source. The present invention uses a dynamic method, that is, a DC bias device is used to dynamically adjust the impedance of the grown graphene, thereby performing dynamic verification. The specific functions of the present invention include: first, perfect absorption of incident waves and dynamic tuning of the intermediate frequency absorption frequency in the X-band, which can be used for electromagnetic stealth, mechanical plane monitoring and other applications; second, perfect absorption of incident waves and dynamic tuning of the absorption amplitude, which can be used for electromagnetic camouflage, electromagnetic deception and other applications, paving the way for the flexible and adaptive application scenarios of graphene in the microwave band. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the unfolded structure of a graphene-based flexible electro-reconfigurable wave-absorbing surface;

[0028] Figure 2 This is a cross-sectional view of a graphene-based flexible electro-reconfigurable absorbing surface;

[0029] Figure 3 are the test results of the frequency reconfigurability of the wave-absorbing surface structure of the present invention under different DC voltages;

[0030] Figure 4 These are the test results of the amplitude reconfigurability of the wave-absorbing surface structure of the present invention under different DC voltages.

[0031] Among them are: a first PET substrate 11, a second PET substrate 12, a first graphene layer 21, a second graphene layer 22, a first PDMS dielectric layer 3, a third PET substrate 41, a fourth PET substrate 42, a first graphene strip 51, a second graphene strip 52, a patterned multilayer graphene square array 6, a second PDMS dielectric layer 7, a multilayer graphene backplane 8, a graphene capacitor 9, and a patterned graphene capacitor 10. DETAILED DESCRIPTION

[0032] The structure and performance of the present invention will be further described below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, the graphene-based flexible electro-reconfigurable wave-absorbing surface structure includes a graphene capacitor 9, a first PDMS dielectric layer 3, a patterned graphene capacitor 10, a patterned multilayer graphene square array 6, a second PDMS dielectric layer 7 and a multilayer graphene backplane 8 which are stacked in sequence;

[0034] The graphene capacitor 9 includes, in sequence, a first PET substrate 11, a first graphene layer 21 arranged on the first PET substrate, a second graphene layer 22 arranged on the second PET substrate, a second PET substrate 12, and a capacitor diaphragm paper impregnated with ionic liquid filled between the first PET substrate and the second PET substrate; the first PET substrate and the second PET substrate are overlapped, and the first graphene layer and the second graphene layer are respectively arranged on the inner surfaces of the first PET substrate and the second PET substrate.

[0035] The patterned graphene capacitor 10 includes, in sequence, a third PET substrate 41, a first graphene strip 51 arranged on the third PET substrate, a second graphene strip 52 arranged on a fourth PET substrate, a fourth PET substrate 42, and a capacitor diaphragm paper impregnated with ionic liquid filled between the third PET substrate 41 and the fourth PET substrate 42; the third PET substrate 41 and the fourth PET substrate 42 are arranged in a superimposed manner, and the first graphene strip 51 and the second graphene strip 52 are respectively arranged on the inner surfaces of the third PET substrate 41 and the fourth PET substrate 42.

[0036] The first graphene strip 51 and the second graphene strip 52 have the same pattern; the first graphene strip 51 and the second graphene strip 52 both include graphene strip units that are periodically arranged at equal intervals; the graphene strip units are rectangular, and the graphene strip units on the first graphene strip 51 and the graphene strip units on the second graphene strip 52 correspond one to one.

[0037] The patterned multilayer graphene square array 6 includes periodically arranged multilayer graphene units, each multilayer graphene unit is arranged in one-to-one correspondence with the graphene strip unit, and the center points of the two coincide.

[0038] The method for preparing the graphene-based flexible electro-reconfigurable wave-absorbing surface structure of the present invention comprises the following steps:

[0039] Step 1, using matlab and equivalent circuit theory to model the graphene capacitor 9, the first PDMS dielectric layer 3, the patterned graphene capacitor 10, the patterned multilayer graphene square array 6, the second PDMS dielectric layer 7 and the multilayer graphene backplane 8. When the incident electromagnetic wave is vertically incident, the first and second monolayer graphenes are equivalent to resistors in parallel; the first graphene strip 51 and the second graphene strip 52 are equivalent to the series connection of a resistor, a capacitor and an inductor; the patterned multilayer graphene square array 6 is equivalent to a capacitor; the PET substrate, the first PDMS dielectric layer 3, the second PDMS dielectric layer 7, and the multilayer graphene backplane 8 are characterized by their respective standard transmission line models;

[0040] The formulas for equivalent resistance, inductance, and capacitance can be found in MY Geng, ZG Liu, WJ Wu, H. Chen, B. Wu, & W. B. Lu, “A Dynamically Tunable Microwave Absorber Based on Graphene,” IEEE Trans. Antennas Propag. 68, 6, 4706, 2020.

[0041] Through parameter scanning, the optimal graphene square resistance, graphene strip unit size, graphene strip unit spacing, patterned graphene square resistance, square multilayer graphene unit size and PDMS dielectric layer thickness for dynamic reconfigurable function were optimized.

[0042] When the size of the graphene strip unit is a rectangle of 5.0mm*6.0mm, the interval of the graphene strip unit is 1.0mm, and the size of the square multilayer graphene unit is 4.2mm*4.2mm, the wave-absorbing surface structure of the present invention has good dynamic reconfiguration function, including independent frequency dynamic continuous reconfiguration and amplitude dynamic continuous reconfiguration.

[0043] At the same time, the thickness of the PET substrate used in the present invention is 120 μm, and the relative dielectric constant is 3.0; the relative dielectric constant of the first PDMS dielectric layer 3 and the second PDMS dielectric layer 7 is 2.8, and the thickness is 1 mm; the structural period of the graphene strip unit is 6.0 mm; the patterned multilayer graphene square array 6 is a periodic structure, in which the structural period is 4.2 mm.

[0044] Step 2, according to step 1, the square resistance of the graphene patterned graphene is obtained, and the graphene is grown by using copper foil, and the growth method is CVD method. After the growth, the graphene is transferred to the first and second PET substrates and the third and fourth PET substrates;

[0045] According to the graphene strip unit size and the graphene strip unit interval obtained in step 1, the graphene on the third PET substrate 41 and the fourth PET substrate 42 is etched by laser to obtain a first graphene strip 51 attached to the third PET substrate 41 and a second graphene strip 52 attached to the fourth PET substrate 42;

[0046] Step 3, filling capacitor diaphragm paper soaked in ionic liquid between the first and second PET substrates to form a graphene capacitor;

[0047] Step 4, filling capacitor diaphragm paper soaked in ionic liquid between the third and fourth PET substrates to form a patterned graphene capacitor;

[0048] Step 5, attaching a patterned multilayer graphene square array 6 and a multilayer graphene back plate 8 to two surfaces of the second PDMS dielectric layer 7 respectively; the size of the patterned multilayer graphene square array 6 is the same as the size of the multilayer graphene unit obtained in step 1;

[0049] Step 6, the patterned graphene capacitor 10 is bonded to the second PDMS dielectric layer 7 to which the patterned multilayer graphene square array 6 and the multilayer graphene backplane 8 are attached, wherein the patterned multilayer graphene square array 6 is bonded to the fourth PET substrate 42;

[0050] Step 7, the graphene capacitor 9, the first PDMS dielectric layer 3 and the structure obtained in the above step 6 are bonded together to form the entire reconfigurable absorbing surface;

[0051] The designed model was modeled using the commercial software CST, and the graphene array was simulated using the time domain simulation method. The patterned graphene was simulated using the impedance boundary condition of zero thickness. The square resistance of the graphene was taken at equal intervals of 100Ω / sq in the region of 200Ω / sq to 1500Ω / sq. The boundary condition imposed on the model was an open boundary, and the characteristics of the absorbing surface, such as the transmission coefficient and reflection coefficient, were obtained by simulation.

[0052] After the dynamic frequency modulation wave absorbing surface structure is prepared according to the method of the present invention, the wave absorption rate characteristics of the flexible electro-reconfigurable wave absorbing surface structure of the present invention are tested.

[0053] First, test the frequency reconfigurable characteristics of the absorbing surface. The test results are as follows: Figure 3As shown in the figure, when DC voltages of 3.5V, 1.7V, 1.4V, 0.8V, 0.1V and 0V are applied to the two ends of the graphene capacitor respectively, when the square resistance of graphene decreases from 1200Ω / sq to 200Ω / sq, the center frequency of the absorbing surface decreases from 10.52GHz to 9.88GHz. At the same time, the reflectivity valley values ​​corresponding to the center frequency are all less than -30dB, which is close to perfect absorption. Based on this, we have achieved dynamic frequency reconfiguration of the absorbing surface in the X-band.

[0054] Second, the amplitude reconfigurable characteristics of the absorbing surface were tested. The test results are as follows: Figure 4 As shown in the figure, when DC voltages of 3.5V, 1.7V, 1.3V, 0.7V, 0.5V, 0.3V and 0.1V are applied to both ends of the graphene capacitor respectively, when the square resistance of graphene is reduced from 1000Ω / sq to 200Ω / sq, the reflection coefficient valley value of the absorbing surface at 10.51GHz is reduced from -48.7dB to -4.4dB, which is close to perfect absorption. Based on this, we have achieved dynamic reconfiguration of the amplitude of the absorbing surface in the X-band.

[0055] Based on the above experimental results, Figure 3 , 4 As shown in the figure, the designed electrically reconfigurable absorbing surface realizes dynamic reconfiguration of the resonance frequency and amplitude respectively. Each layer structure constituting the absorbing surface is flexible and bendable, and the entire absorbing surface does not contain any semiconductor devices such as varactor diodes, etc., thus realizing the flexibility of the absorbing surface structure. This will provide new ideas for the flexible applications of graphene in the microwave band such as electromagnetic stealth and electromagnetic deception.

Claims

1. A graphene-based flexible electro-reconfigurable wave-absorbing surface, characterized in that: The wave-absorbing surface comprises a first PET substrate (11), a first graphene layer (21), a second graphene layer (22), a second PET substrate (12), a first PDMS dielectric layer (3), a third PET substrate (41), a first graphene strip (51), a second graphene strip (52), a fourth PET substrate (42), a patterned multilayer graphene square array (6), a second PDMS dielectric layer (7), and a multilayer graphene backplane (8) which are stacked from top to bottom. The graphene capacitor (9) is composed of a first PET substrate (11), a first graphene layer (21) arranged on the first PET substrate, a second PET substrate (12), a second graphene layer (22) arranged on the second PET substrate, and a capacitor diaphragm paper soaked in ionic liquid filled between the first PET substrate and the second PET substrate; the first PET substrate and the second PET substrate are stacked, and the first graphene layer and the second graphene layer are respectively arranged on the inner surfaces of the first PET substrate and the second PET substrate; A patterned graphene capacitor (10) is formed by a third PET substrate (41), a first graphene strip (51) arranged on the third PET substrate, a fourth PET substrate (42), a second graphene strip (52) arranged on the fourth PET substrate, and a capacitor diaphragm paper soaked in an ionic liquid filled between the third PET substrate and the fourth PET substrate; the third PET substrate and the fourth PET substrate are arranged in a stacked manner, and the first graphene strip and the second graphene strip are arranged on the inner surfaces of the first PET substrate and the second PET substrate, respectively; The patterned multilayer graphene square array (6) comprises a periodically arranged multilayer graphene square unit array, and the patterned multilayer graphene square array (6) and the first graphene strip (51) and the second graphene strip (52) are parallel to each other.

2. The graphene-based flexible electro-reconfigurable absorbing surface according to claim 1, characterized in that: The first graphene layer (21) and the second graphene layer (22) are structurally complete and are not patterned; The first graphene strip (51) and the second graphene strip (52) both comprise graphene strip units that are periodically arranged at equal intervals to form a graphene strip array; the graphene strip units are rectangular, and the graphene strip units on the first graphene strip (51) and the graphene strip units on the second graphene strip (52) correspond one to one.

3. The graphene-based flexible electro-reconfigurable absorbing surface according to claim 1, characterized in that: The thickness of the capacitor diaphragm paper soaked with ionic liquid filled between the first PET substrate (11) and the second PET substrate (12) is 50-100 microns.

4. The graphene-based flexible electro-reconfigurable absorbing surface according to claim 1, characterized in that: The thickness of the capacitor diaphragm paper soaked with ionic liquid filled between the third PET substrate (41) and the fourth PET substrate (42) is 50-100 microns.

5. The graphene-based flexible electro-reconfigurable absorbing surface according to claim 2, characterized in that: The size of the first graphene strip (51) and the second graphene strip (52) units is a 5.0 mm*6.0 mm rectangle, and the interval between the graphene strip units is 1.0 mm.

6. The graphene-based flexible electro-reconfigurable absorbing surface according to claim 1, characterized in that: The unit size of the patterned multilayer graphene square array (6) is 4.2 mm*4.2 mm.

7. A method for preparing a graphene-based flexible electro-reconfigurable wave-absorbing surface as claimed in claim 1, characterized in that: The steps include: Step 1, using Matlab and equivalent circuit theory to model the graphene capacitor, the first PDMS dielectric layer, the patterned graphene capacitor, the patterned graphene square array, the second PDMS dielectric layer and the multilayer graphene backplane, and optimizing the graphene strip unit size, graphene strip unit spacing, graphene square resistance, and the size of the multilayer graphene square unit with the best reconfigurable function through parameter scanning; The graphene on the third PET substrate (41) and the fourth PET substrate (42) is etched by laser to obtain a first graphene strip (51) array attached to the third PET substrate (41) and a second graphene strip (52) array attached to the fourth PET substrate (42); Step 3, filling capacitor diaphragm paper soaked in ionic liquid between the first PET substrate (11) and the second PET substrate (12) to form a graphene capacitor (9); Step 4, filling capacitor diaphragm paper soaked in ionic liquid between the third PET substrate (41) and the fourth PET substrate (42) to form a patterned graphene capacitor (10); Step 5, attaching a patterned multilayer graphene square array (6) and a multilayer graphene backplane (8) to the upper and lower surfaces of the second PDMS dielectric layer (7), respectively; Step 6, the graphene capacitor (9), the first PDMS dielectric layer (3), the patterned graphene capacitor (10), the patterned multilayer graphene square array (6), the second PDMS dielectric layer (7), and the multilayer graphene backplane (8) prepared above are sequentially laminated from top to bottom to form a flexible reconfigurable electro-absorption surface structure.

8. The method for preparing a graphene-based flexible electro-reconfigurable absorbing surface according to claim 7, characterized in that: In step 1, the graphene capacitor, the first PDMS dielectric layer, the patterned graphene capacitor, the patterned graphene square array, the second PDMS dielectric layer and the multilayer graphene backplane are modeled using matlab and equivalent circuit theory; when the incident electromagnetic wave is incident vertically, the unpatterned graphene is equivalent to a resistor; the graphene strip array is equivalent to a series connection of a resistor, a capacitor and an inductor; the patterned graphene square array is equivalent to a capacitor; the first PET substrate (11), the second PET substrate (12), the first PDMS dielectric layer (3), the second PDMS dielectric layer (7), and the multilayer graphene backplane (8) are characterized by their respective standard transmission line models.

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