A metamaterial with mechanically controlled wave absorbing performance and a method for mechanically controlling coupling spacing thereof

Abstract

The present invention discloses a metamaterial with mechanically controlled wave absorption performance and a mechanical control method of coupling spacing thereof, belonging to the technical field of reconfigurable metamaterials. The metamaterial is a double-layer structure, which is composed of a lower metamaterial and an upper metamaterial from bottom to top, and there is a certain spacing between the double-layer structures; the lower metamaterial is composed of a bottom substrate layer, a lower dielectric layer and a lower pattern layer from bottom to top, and the upper metamaterial is composed of an upper pattern layer and an upper dielectric layer from bottom to top, and a periodically arranged pattern structure is arranged thereon, and the pattern structure is geometrically complementary to form a complete closed ring figure. The present invention causes changes in the circuit structure and RLC parameters of an equivalent circuit model through changes in the coupling effect between the interlayer geometrically complementary and centrally symmetrical structures, so that the input impedance of the metamaterial in different states also changes; and a mechanical control module and a fixing device are used to control the change in the interlayer distance of the double-layer metamaterial to achieve the regulation of the overall wave absorption performance of the metamaterial.

Description

Technical Field

[0001] The present invention relates to the technical field of reconfigurable metamaterials, and in particular to a metamaterial with mechanically regulated wave absorbing performance and a method for mechanically regulating coupling spacing thereof. Background Art

[0002] With the development of metamaterial technology, this kind of composite material with artificially designed structure and extraordinary physical properties that natural materials do not have has become more mature. In order to obtain richer functions than traditional metamaterials, reconfigurable metamaterials have come into people's view. By combining with different control methods, the same metamaterial device can have more states. Among them, many applications have appeared in changing the properties of electromagnetic waves. For example, the reflection angle, transmittance, polarization state, etc. of the incident wave can be changed through reconfigurable metamaterials. The most typical one is the reconfigurable microwave absorbing metamaterial, which can provide multiple modes for different absorbing needs.

[0003] The prior art proposes a reconfigurable method of electrical control, that is, adding electronic components (varicap diodes, PIN diodes, etc.) or electrically responsive materials (graphene, electrochromic materials, etc.) to metamaterials, and changing the on and off of electronic components or the properties of electrically responsive materials by adding bias voltage. Due to the inherent properties of electronic components and electrically responsive materials, the needs of switching between more modes cannot be met, such as electronic components; the wide range of changes in absorption rate cannot be met, such as graphene and electrochromic materials; in addition to the above limitations, the above control methods also have the disadvantage of additional energy consumption. At present, although certain progress has been made in this field, a simple and ingenious design idea is still needed to integrate the continuous gradual change of adjustable performance, a large adjustment range and green energy saving, which is of great significance to the functional integration and potential applications of reconfigurable absorbing metamaterials. Based on the above analysis, the conception and design of structures and control methods that meet the above conditions are related to the potential applications and development prospects of reconfigurable absorbing metamaterials. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to propose a metamaterial with mechanically controlled wave absorption performance and a method for mechanically controlling the coupling spacing thereof. The present invention causes changes in the circuit structure and RLC parameters of the equivalent circuit model through changes in the coupling effect between the interlayer geometrically complementary and centrally symmetrical structures, so that the input impedance of the metamaterial in different states also changes. From the transmission line theory in the electromagnetic wave theory, it can be obtained that:

[0005]

[0006] A(ω)=1-R(ω)

[0007] Among them, R(ω) is the reflectivity, A(ω) is the absorptivity, and Z inis the input impedance of the metamaterial, and Z0 is the characteristic impedance of free space;

[0008] The degree of matching between the input impedance and the characteristic impedance of free space determines the absorption rate of the metamaterial to the incident wave, which causes the absorption rate to change continuously. Due to the form of geometric complementary structure, the absorption performance of the metamaterial can change continuously from the strong absorption mode to the weak absorption mode in the process of geometrically complementing the complete shape to separating far away. In addition, when the two-layer structure is aligned and vertically projected, a long strip of overlapping area will be displayed at the left and right edges of each sub-block structure. The mechanical control module and the fixing device are used to control the change of the distance between the two-layer metamaterial layers to achieve the regulation of the overall wave absorption performance of the metamaterial. Due to the advantages of fast response and in-place locking of the mechanical control itself, no additional energy consumption will be generated during the standby time. Combining the above principles and methods, it is possible to achieve continuous adjustable wave absorption performance, wide adjustment range and integration of green energy-saving functions.

[0009] The present invention is achieved through the following technical solutions:

[0010] A metamaterial with mechanically controlled wave absorbing properties, the metamaterial being a double-layer structure, the double-layer structure consisting of a lower metamaterial and an upper metamaterial from bottom to top, with a certain distance between the lower metamaterial and the upper metamaterial; the lower metamaterial consisting of a bottom substrate layer 1, a lower dielectric layer 2 and a lower pattern layer 3 from bottom to top, the upper metamaterial consisting of an upper pattern layer 4 and an upper dielectric layer 5 from bottom to top, the lower pattern layer 3 and the upper pattern layer 4 both being provided with periodically arranged pattern structures, and the pattern structures of the lower pattern layer 3 and the upper pattern layer 4 being geometrically complementary and centrally symmetrical, and being able to complement each other into a complete closed ring figure.

[0011] Furthermore, the closed annular figure is a circular ring, a triangular ring, a quadrilateral ring or a polygonal ring.

[0012] Furthermore, the size of the metamaterial having a single periodically arranged pattern structure is 1 / 6-1 / 2 of the center frequency wavelength of the target frequency range.

[0013] Furthermore, the spacing between the lower metamaterial and the upper metamaterial is 0-7 mm.

[0014] Furthermore, an air layer is included between the lower pattern layer 3 and the upper pattern layer 4 .

[0015] Furthermore, the lower surface of the lower dielectric layer 2 is bonded to the bottom substrate layer 1 by a glue; the lower pattern layer 3 is bonded to the upper surface of the lower dielectric layer 2 by hot pressing or magnetron sputtering, and the upper pattern layer 4 is bonded to the lower surface of the upper dielectric layer 5 by hot pressing or magnetron sputtering.

[0016] Furthermore, the material of the bottom substrate layer 1 is a good metal conductor or a material with extremely low sheet resistance, so that the metamaterial transmittance is 0.

[0017] Furthermore, the bottom substrate layer 1 is a transparent metal grid, a low-resistance film such as PET-based ITO, or a non-transparent conductive metal material;

[0018] The dielectric constant and thickness of the materials of the lower dielectric layer 2 and the upper dielectric layer 5 should match each other, that is, satisfy the impedance value of the dielectric layer position in the equivalent circuit model; the materials of the lower dielectric layer 2 and the upper dielectric layer 5 are non-magnetic materials, and the materials of the lower dielectric layer 2 and the upper dielectric layer 5 are glass, PET, and PDMS materials; the materials of the lower pattern layer 3 and the upper pattern layer 4 are flexible / rigid / optically transparent / optically non-transparent conductive materials.

[0019] Furthermore, the pattern structures on the lower pattern layer 3 and the upper pattern layer 4 are processed on the basis of the substrate. Specifically, the pattern structure is prepared by a chemical etching process for the copper-clad laminate substrate, and the pattern structure is prepared by a photolithography etching process for the magnetron sputtered conductor film (ITO, silver, gold, etc.).

[0020] On the other hand, the present invention provides a method for mechanically controlling the coupling spacing of a metamaterial with mechanically controlled wave absorbing performance, which specifically comprises the following steps:

[0021] Step 1: Build a control device, which includes a fixing device, a precision electric-controlled lifting platform and a mechanical control module; the precision electric-controlled lifting platform is located directly below the fixing device, and the mechanical control module is connected to the precision electric-controlled lifting platform;

[0022] Step 2: fix the upper metamaterial on a fixing device; fix the lower metamaterial on a precision electric-controlled lifting platform, wherein the upper pattern layer 4 of the upper metamaterial corresponds to the pattern structure of the lower pattern layer 3 of the lower metamaterial;

[0023] Step 3: Control the up and down movement of the precision electric-controlled lifting platform through the mechanical control module to achieve the coupling distance control between the lower metamaterial and the upper metamaterial.

[0024] Furthermore, the fixing device is composed of a "U"-shaped wooden board and four supporting wooden sticks, wherein the lower surface of the "U"-shaped wooden board is used to stick the edges of the upper metamaterial on it, and when preparing the upper metamaterial, a part with the same width as the "U"-shaped wooden board must be left around the actual sample for connection.

[0025] Furthermore, the mechanical control module is electrically driven, knob driven or slide rail driven.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) Compared with traditional and electrically controlled metamaterials, the present invention has a more flexible control freedom and a continuous switching function of strong / weak absorption rate due to the double-layer metamaterial design, through the geometric complementary relationship between the upper pattern layer and the lower pattern layer and the overlapping area that enhances the complementary performance;

[0028] (2) The present invention adjusts the interlayer distance by introducing a fixing device and a mechanical control module, and energy is consumed only when moving. The components of the entire metamaterial are all passive materials, and there is no additional energy consumption, no standby energy consumption, and it conforms to the concept of green environmental protection;

[0029] (3) The pattern structure and metamaterial components proposed in the present invention are universal. As long as the designed unit structure satisfies its material layer matching and the center / non-center symmetric complementary design of the conductive material pattern, it can exhibit mechanically controlled absorbing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0031] Figure 1 A schematic diagram of a unit structure of a metamaterial with mechanically controlled wave absorbing performance according to the present invention;

[0032] Among them, from bottom to top, they are bottom substrate layer 1, lower dielectric layer 2, lower pattern layer 3, interlayer air layer, upper pattern layer 4, and upper dielectric layer 5;

[0033] Figure 2 Schematic diagram of the top view of the unit structure of the lower pattern layer 3 of the present invention;

[0034] Figure 3 It is a bottom view structural diagram of the unit structure of the upper pattern layer 4 of the present invention;

[0035] in, Figure 2 , Figure 3 Different shades represent different materials, and the pattern is attached to the surface of the substrate;

[0036] Figure 4 It is a schematic structural diagram of the fixing device of the present invention;

[0037] In the figure: a is the location where the upper metamaterial is attached, and b is the location of the precision electric-controlled lifting platform;

[0038] Figure 5 It is a schematic diagram of the composition of the mechanical control module and the precise electric control lifting of the present invention;

[0039] Among them, the lower layer of metamaterial is placed on the precision electric control lifting platform; the stepper motor control chassis is used to control the movement of the lifting platform;

[0040] Figure 6 This is a measured graph of emission intensity corresponding to different interlayer spacings of the present invention;

[0041] Among them, the target frequency domain is 8-12GHz, the range of interlayer spacing is 0-7mm, and the three-dimensional graph composed of the reflection intensity corresponding to each state;

[0042] Figure 7 Schematic diagram of the test environment of the sample of the present invention;

[0043] Among them, from left to right are a control computer 6, a vector network instrument 7, a horn antenna 8, a sample placement platform 9, a fully automatic arch frame 10 and an arch frame control box 11. DETAILED DESCRIPTION

[0044] In order to clearly and completely describe the technical solution and its specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings of the specification:

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment provides a metamaterial with mechanically controlled wave absorbing performance, wherein the metamaterial is a double-layer structure, and the double-layer structure is composed of a lower metamaterial and an upper metamaterial from bottom to top, and there is a certain distance between the lower metamaterial and the upper metamaterial; the lower metamaterial is composed of a bottom substrate layer 1, a lower dielectric layer 2 and a lower pattern layer 3 from bottom to top, and the upper metamaterial is composed of an upper pattern layer 4 and an upper dielectric layer 5 from bottom to top, and the lower pattern layer 3 and the upper pattern layer 4 are both provided with periodically arranged pattern structures, and the pattern structures of the lower pattern layer 3 and the upper pattern layer 4 are geometrically complementary and centrally symmetrical, and can complement each other into a complete closed ring figure.

[0047] Furthermore, the closed annular figure is a circular ring, a triangular ring, a quadrilateral ring or a polygonal ring.

[0048] Furthermore, the size of the metamaterial having a single periodically arranged pattern structure is 1 / 6-1 / 2 of the center frequency wavelength.

[0049] Furthermore, the spacing between the lower metamaterial and the upper metamaterial is 0-7 mm.

[0050] Furthermore, an air layer is included between the lower pattern layer 3 and the upper pattern layer 4 .

[0051] Furthermore, the lower surface of the lower dielectric layer 2 is bonded to the bottom substrate layer 1 by a glue; the lower pattern layer 3 is bonded to the upper surface of the lower dielectric layer 2 by hot pressing or magnetron sputtering, and the upper pattern layer 4 is bonded to the lower surface of the upper dielectric layer 5 by hot pressing or magnetron sputtering.

[0052] Furthermore, the material of the bottom substrate layer 1 is a good metal conductor or a material with extremely low sheet resistance, so that the metamaterial transmittance is 0.

[0053] Furthermore, the bottom substrate layer 1 is a transparent metal grid, a low-resistance film such as PET-based ITO, or a non-transparent conductive metal material.

[0054] Furthermore, the dielectric constant and thickness of the materials of the lower dielectric layer 2 and the upper dielectric layer 5 should match each other, that is, satisfy the impedance value of the dielectric layer position in the equivalent circuit model; the materials of the lower dielectric layer 2 and the upper dielectric layer 5 are non-magnetic materials, and the materials of the lower pattern layer 3 and the upper pattern layer 4 are conductive materials.

[0055] Furthermore, the materials of the lower dielectric layer 2 and the upper dielectric layer 5 are glass, PET, and PDMS materials; the materials of the lower pattern layer 3 and the upper pattern layer 4 are flexible / rigid / optically transparent / optically non-transparent materials.

[0056] Furthermore, the pattern structures on the lower pattern layer 3 and the upper pattern layer 4 are processed on the basis of the substrate. Specifically, the pattern structure is prepared by a chemical etching process for the copper-clad laminate substrate, and the pattern structure is prepared by a photolithography etching process for the magnetron sputtered conductor film (ITO, silver, gold, etc.).

[0057] Example 2

[0058] The present embodiment provides a metamaterial with mechanically controlled wave absorbing performance, wherein the metamaterial is a double-layer structure, which consists of a lower metamaterial and an upper metamaterial from bottom to top, and there is a certain distance between the lower metamaterial and the upper metamaterial; the lower metamaterial consists of a bottom substrate layer 1, a lower dielectric layer 2 and a lower pattern layer 3 from bottom to top, and the upper metamaterial consists of an upper pattern layer 4 and an upper dielectric layer 5 from bottom to top, and periodically arranged pattern structures are provided on the lower pattern layer 3 and the upper pattern layer 4, and the pattern structures of the lower pattern layer 3 and the upper pattern layer 4 are geometrically complementary and centrally symmetrical, and can complement each other to form a complete closed ring figure.

[0059] like Figure 1In this embodiment, the bottom substrate layer 1 is a transparent metal grid, the lower dielectric layer 2 is quartz glass, the lower pattern layer 3 is ITO, the upper pattern layer 4 is ITO, and the upper dielectric layer 5 is PET.

[0060] like Figure 2 and Figure 3 As shown, the closed ring figure of this embodiment is a circular ring structure, and the pattern structures on the lower pattern layer 3 and the upper pattern layer 4 are composed of four identical small parts. When the pattern structures of the upper and lower layers are aligned and vertically projected, the same long strip area is displayed at the left and right edges of each small pattern. The width of the overlapping long strips in this embodiment is 0.025mm.

[0061] Example 3

[0062] In order to reduce the effect and alignment difficulty when forming a closed circle, each small ITO pattern should have a 0.02-0.06mm wide strip overlapping area at the left and right edges. In this embodiment, the width of the overlapping strips is 0.025mm.

[0063] This embodiment provides a method for preparing a geometric complementary pattern layer by using magnetron sputtering and photolithography etching process, and the specific steps are as follows:

[0064] For the magnetron sputtering process, magnetron sputtering of ITO was performed on the upper surface of the lower dielectric layer 2 and the lower surface of the upper dielectric layer 5, respectively, so that an ITO film with a thickness of 45 nm was deposited on both surfaces, completing the ITO coating; for the photolithography process, firstly, the shapes and period numbers of the two mask plates were designed respectively according to the specific pattern size and requirements; secondly, the ITO surface was cleaned with a glass cleaning agent, rinsed with deionized water and blown dry with an air gun; then, 512 photoresist was statically spin-coated on the upper surface of the lower dielectric layer 2 and the lower surface of the upper dielectric layer 5, with a rotation speed of 2000 r / min, a time of 30 s, and a 100° back-off angle. Fire for 5 minutes; then, add a mask and perform UV exposure for 50 seconds; then, perform a development operation, use a 0.4wt% NaOH solution, soak for 20 seconds, remove the photoresist in the exposed area, rinse the residual NaOH solution with deionized water and blow dry; next, perform etching, soak with etching solution for 3-5 minutes, rinse with deionized water and blow dry, use a multimeter to test whether the etched area is etched clean; then perform an alkaline cleaning operation, soak with 4wt% NaOH solution for 1-2 minutes, take out the photoresist in the unexposed area after complete reaction, rinse with deionized water and blow dry; finally, perform a stripping operation, use a high-power Plasma for 30 minutes to remove the residual photoresist, and prepare a geometric complementary pattern layer.

[0065] Example 4

[0066] This embodiment provides a method for mechanically controlling the coupling spacing of a metamaterial with mechanically controlled wave absorbing performance, which specifically includes the following steps:

[0067] Step 1: If Figure 4 and Figure 5 As shown, a control device is constructed, and the control device includes a fixing device, a precision electric-controlled lifting platform and a mechanical control module; the precision electric-controlled lifting platform is located directly below the fixing device, and the mechanical control module is connected to the precision electric-controlled lifting platform;

[0068] Step 2: fix the upper metamaterial on a fixing device; fix the lower metamaterial on a precision electric-controlled lifting platform, wherein the upper pattern layer 4 of the upper metamaterial corresponds to the pattern structure of the lower pattern layer 3 of the lower metamaterial;

[0069] Step 3: Control the precise electric-controlled lifting platform to move up and down through the mechanical control module to adjust the coupling distance between the lower metamaterial and the upper metamaterial.

[0070] like Figure 4 As shown, the structure of the fixing device is introduced in detail below. The fixing device consists of a "U"-shaped wooden board and four supporting wooden sticks, wherein the lower surface of the "U"-shaped wooden board is used to stick the edges of the upper metamaterial on it. When preparing the upper metamaterial, a part with the same width as the "U"-shaped wooden board must be left around the actual sample for connection.

[0071] In this embodiment, the width of the "U"-shaped wooden board is 32 mm, the thickness is 5 mm, the inner circle size of the "U"-shaped wooden board is 268 mm × 268 mm, and the outer circle size is 300 mm × 300 mm;

[0072] In this embodiment, the wooden stick used as support and height control for the fixing device is 100 mm long, and both the length and width are 15 mm;

[0073] In this embodiment, the actual size of the sample of the upper metamaterial is 283 mm × 283 mm;

[0074] In this embodiment, the length of the supporting wooden stick is the sum of the maximum distance between the layers and the minimum height of the precision electric control lifting platform, which can satisfy the change between the maximum and minimum distances during mechanical regulation;

[0075] In this embodiment, the precision of the precision electric-controlled lifting platform used is 0.01 mm; the platform size is 150 mm × 230 mm; the maximum operating speed is 20 mm / s;

[0076] Use the built fixture and mechanical control module to actually change the interlayer distance and plot the reflection intensity data as shown below. Figure 6The three-dimensional result diagram of actual measurement of interlayer spacing-frequency-reflection intensity shown in the figure can further obtain the dynamic wave absorption performance of the metamaterial of the present invention with an absorption rate between 10% and 90%.

[0077] In the mechanical control test, the movement of the lower metamaterial is continuous and no mutation occurs. This also leads to the continuous change of the reflectivity and absorptivity of the metamaterial, realizing the switching of the incident wave absorptivity, and then showing the continuous regulation of absorptivity and reflectivity over a wide range. First, adjust the interlayer spacing to 0, and align the pattern layer at the same time so that the two form a closed loop. At this time, the state of the metamaterial of the present invention is Figure 6 At a in the figure (the interlayer distance is 0 mm); increase the interlayer distance from 0 to Figure 6 The middle ab segment (interlayer distance is 0-0.7mm) is the strong coupling area between metamaterial layers; the bc segment (interlayer distance is 0.7-4mm) is the weakened coupling area between metamaterial layers; the cd segment (interlayer distance is 4-7mm) is the decoupling area between metamaterial layers. Since the reflection intensity and the interlayer distance are monotonic functions, in the mechanical control method of this example, the reflection intensity and the interlayer distance can be tabulated one by one according to the measured three-dimensional graph, and the required position value can be directly input into the stepper motor control chassis when moving.

[0078] Example 5

[0079] like Figure 7 As shown, this embodiment provides an experimental environment for performance testing of the above-mentioned samples, and the experimental environment is composed of a control part and a test part; the control part is composed of a control computer 6 and an arch frame control chassis 11, and the test part is composed of a vector network instrument 7, a horn antenna 8, a sample placement platform 9 and a fully automatic arch frame 10.

[0080] Furthermore, the control computer 6 is a master control device, which is connected to the vector network instrument 7 and the arch frame control box 11 through a network cable and a USB cable respectively to perform signal transmission.

[0081] Furthermore, the vector network instrument 7 is a device for generating and receiving signals, and is connected to two horn antennas 8 via two coaxial lines.

[0082] Furthermore, two horn antennas 8 are fixed on the guide rail of the fully automatic arch frame 10, which are a transmitting antenna and a receiving antenna respectively; the transmitting antenna is used to transmit the electromagnetic signal generated by the vector network instrument 7, and the receiving antenna is used to receive the electromagnetic signal reflected back by the sample and transmit the signal back to the vector network instrument 7.

[0083] Furthermore, the arch control box 11 receives the control signal of the control computer 6 and is connected to the full-automatic arch 10 through a cable to accurately change the position of the horn antenna 8.

[0084] Furthermore, the sample placement platform 9 is used to place the sample to be tested (such as Figure 1 as shown) and the sample fixing device (as shown Figure 4 shown).

[0085] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above-mentioned embodiments. Within the technical concept of the present invention, the technical scheme of the present invention can be subjected to a variety of simple deformations, and these simple deformations all belong to the protection scope of the present invention. The present invention has made a universal description within the framework of the design structure of the metamaterial, the specific shape of the geometrically complementary central symmetric / asymmetric pattern, and the selection of materials.

[0086] It should also be noted that the various specific technical features described in the above-mentioned specific mechanical control methods can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will no longer separately describe various possible combinations.

[0087] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A metamaterial with mechanically controlled wave absorbing properties, characterized in that: The metamaterial is a double-layer structure, which consists of a lower metamaterial and an upper metamaterial from bottom to top, with a certain distance between the lower metamaterial and the upper metamaterial; the lower metamaterial consists of a bottom substrate layer (1), a lower dielectric layer (2) and a lower pattern layer (3) from bottom to top, and the upper metamaterial consists of an upper pattern layer (4) and an upper dielectric layer (5) from bottom to top, and the lower pattern layer (3) and the upper pattern layer (4) are both provided with a periodically arranged pattern structure, and the pattern structures of the lower pattern layer (3) and the upper pattern layer (4) are geometrically complementary and both are centrally symmetrical, and can complement each other to form a complete closed ring shape; The closed ring shape is a circular ring, a triangular ring, a quadrilateral ring or a polygonal ring; the size of the metamaterial having a single periodically arranged pattern structure is 1 / 6-1 / 2 of the center frequency wavelength of the target frequency domain range; An air layer is also included between the lower pattern layer (3) and the upper pattern layer (4); The bottom substrate layer (1) is a transparent metal grid, a PET-based ITO low-resistance film, or a non-transparent conductive metal material; The dielectric constant and thickness of the materials of the lower dielectric layer (2) and the upper dielectric layer (5) should match each other, that is, satisfy the impedance value of the dielectric layer position in the equivalent circuit model; the materials of the lower dielectric layer (2) and the upper dielectric layer (5) are glass, PET, and PDMS materials; and the materials of the lower pattern layer (3) and the upper pattern layer (4) are flexible / rigid / optically transparent / optically non-transparent conductive materials.

2. The metamaterial with mechanically controlled wave absorbing properties according to claim 1, characterized in that: The distance between the lower metamaterial and the upper metamaterial is 0-7 mm.

3. The metamaterial with mechanically controlled wave absorbing properties according to claim 1, characterized in that: The lower surface of the lower dielectric layer (2) and the bottom substrate layer (1) are bonded together by means of a glue; the lower pattern layer (3) is bonded to the upper surface of the lower dielectric layer (2) by means of hot pressing or magnetron sputtering; and the upper pattern layer (4) is bonded to the lower surface of the upper dielectric layer (5) by means of hot pressing or magnetron sputtering.

4. The metamaterial with mechanically controlled wave absorbing properties as claimed in claim 1, characterized in that: The pattern structures on the lower pattern layer (3) and the upper pattern layer (4) are processed on the basis of the substrate. Specifically, the pattern structure is prepared by a chemical etching process for the copper clad laminate substrate, and the pattern structure is prepared by a photolithography etching process for the magnetron sputtered conductor film.

5. A method for mechanically controlling the coupling spacing of a metamaterial with mechanically controlled wave absorbing performance as claimed in claim 1, characterized in that: The specific steps include: Step 1: Build a control device, which includes a fixing device, a precision electric-controlled lifting platform and a mechanical control module; the precision electric-controlled lifting platform is located directly below the fixing device, and the mechanical control module is connected to the precision electric-controlled lifting platform; Step 2: fixing the upper metamaterial on a fixing device; fixing the lower metamaterial on a precision electric-controlled lifting platform, wherein the upper pattern layer (4) of the upper metamaterial corresponds to the pattern structure of the lower pattern layer (3) of the lower metamaterial; Step 3: Control the up and down movement of the precision electric-controlled lifting platform through the mechanical control module to achieve the coupling distance control between the lower metamaterial and the upper metamaterial.

6. A method for mechanically controlling the coupling spacing of a metamaterial with mechanically controlled wave absorbing performance as claimed in claim 5, characterized in that: The fixing device consists of a "U"-shaped wooden board and four supporting wooden sticks, wherein the lower surface of the "U"-shaped wooden board is used to stick the edges of the upper metamaterial on it. When preparing the upper metamaterial, a part with the same width as the "U"-shaped wooden board should be left around the actual sample for connection.

7. A method for mechanically controlling the coupling spacing of a metamaterial with mechanically controlled wave absorbing performance as claimed in claim 5, characterized in that: The mechanical control module is electrically driven, knob driven or slide rail driven.

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