Metasurface unit and reconfigurable electromagnetic metasurface

Abstract

This invention relates to the field of artificial electromagnetic materials, and more particularly to a metasurface unit and a reconfigurable electromagnetic metasurface. The metasurface unit includes a metal reflective layer, a dielectric layer, flexible actuators, a metal response layer, and a drive control unit. Multiple flexible actuators are fixed in a two-dimensional array on the side of the dielectric layer away from the metal reflective layer. The flexible actuators have both spreading and contracting forms; two adjacent flexible actuators are interconnected when in the spreading form. The drive control unit is electrically connected to each flexible actuator and controls each flexible actuator to switch between spreading and contracting forms. This invention, by incorporating flexible actuators within the metasurface unit and controlling each actuator to switch between spreading and contracting forms, allows the metasurface unit to independently realize multiple structural forms. Therefore, the metasurface unit possesses higher degrees of freedom, a wider reconfigurable bandwidth, and more flexible and controllable electromagnetic wave manipulation capabilities.

Description

Technical Field

[0001] This invention relates to the field of artificial electromagnetic materials, and more particularly to a metasurface unit and a reconfigurable electromagnetic metasurface. Background Technology

[0002] Artificial electromagnetic metasurfaces are arrays of two-dimensional planes composed of subwavelength metal / dielectric structures. They can flexibly and effectively control various electromagnetic wave characteristics, including phase, frequency, amplitude, and polarization. Based on these characteristics, electromagnetic metasurfaces can perform various functions such as beam deflection, polarization conversion, perfect absorption, and amplitude modulation, thereby achieving arbitrary control of electromagnetic waves. They have found wide applications in high-resolution imaging, wireless communication, and stealth technology.

[0003] In recent years, with the development of wireless communication and information processing technologies, the fixed artificial unit structure of traditional electromagnetic metasurfaces means that once formed, the electromagnetic response characteristics of the metasurface are also fixed. Faced with increasingly complex electromagnetic environments, this makes it impossible to flexibly and effectively control electromagnetic waves and lacks real-time processing capabilities. Therefore, how to achieve excellent electromagnetic wave manipulation performance while simultaneously realizing the reconfigurability of electromagnetic metasurfaces has become a top priority in electromagnetic metasurface research. In recent years, research on reconfigurable electromagnetic metasurfaces has become increasingly in-depth. Currently, the reconfigurability of electromagnetic metasurfaces is mainly achieved through lumped elements, functional materials, and mechanical structures. However, the introduction of lumped elements, including PIN diodes and varactor diodes, often leads to excessively high electromagnetic losses; functional materials, including liquid crystals and phase change materials, often have poor tuning capabilities due to their high tuning difficulty; and mechanical tuning methods, including microfluidics and stretching structures, often face the problem of integrating mechanical devices with electromagnetic metasurfaces. Summary of the Invention

[0004] The objective of this invention is to at least solve the problem of the single response mode of metasurface units. This objective is achieved through the following technical solution:

[0005] A first aspect of the present invention provides a metasurface unit comprising:

[0006] Metal reflective layer;

[0007] A dielectric layer that covers one side of the metal reflective layer;

[0008] Multiple flexible actuators are fixed in a two-dimensional array on the side of the dielectric layer away from the metal reflective layer. The flexible actuators have an extended shape and a contracted shape. When two adjacent flexible actuators are in the extended shape, they are interconnected. When one of the two adjacent flexible actuators is in the contracted shape, they are not interconnected.

[0009] A metallic responsive layer covers the side of the flexible actuator away from the dielectric layer;

[0010] A drive control unit is electrically connected to each of the flexible actuators, and the drive control unit is used to control each of the flexible actuators to convert into an unfolding or contracting state.

[0011] According to the metasurface unit of the present invention, flexible actuators are provided in the metasurface unit and electrically connected to a drive control unit. The drive control device can control each flexible actuator to convert into an unfolding or contracting state, thus enabling independent control of each flexible actuator. When two adjacent flexible actuators are in an unfolding state, they are interconnected; conversely, when adjacent flexible actuators are in a contracting state, they are not interconnected. This allows the metasurface unit to independently realize multiple structural forms, thus giving it higher degrees of freedom, wider reconfigurable bandwidth, more flexible and controllable electromagnetic wave manipulation capabilities, and enriching the response modes.

[0012] In addition, the metasurface unit according to the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, the flexible actuator is cross-shaped, and the bottom center of the flexible actuator is fixed to the dielectric layer.

[0014] In some embodiments of the present invention, the flexible actuator is made of an ionoactive polymer, a liquid crystal elastomer, a shape memory polymer, or a hydrogel.

[0015] In some embodiments of the present invention, the material of the metal response layer is liquid metal or metal sputtering film.

[0016] In some embodiments of the present invention, the liquid metal is a gallium indium tin alloy.

[0017] In some embodiments of the present invention, the liquid metal is coated onto the flexible actuator by screen printing.

[0018] In some embodiments of the present invention, the material of the metal reflective layer is copper.

[0019] In some embodiments of the present invention, the drive control unit controls the flexible actuator to change its form by voltage control, electrostatic control, temperature control, light control, or pH control.

[0020] In some embodiments of the present invention, the drive control unit controls the flexible actuator to change form by voltage control. The drive control unit includes a plurality of metal electrodes and a drive control device. The drive control device is electrically connected to the metal electrodes, and each metal electrode is connected to a corresponding flexible actuator.

[0021] A second aspect of the present invention provides a reconfigurable electromagnetic metasurface comprising the metasurface unit described above.

[0022] According to the present invention, the reconfigurable electromagnetic metasurface comprises metasurface units. Each metasurface unit, through a drive control unit, can achieve independent control of each flexible actuator. Therefore, the reconfigurable electromagnetic metasurface unit can independently realize multiple structural forms, enabling dynamic and flexible adjustment of the reconfigurable electromagnetic metasurface and satisfying the high-degree-of-freedom real-time adjustment capability of the reconfigurable electromagnetic metasurface. Attached Figure Description

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0024] Figure 1 A schematic diagram of the structure of a metasurface unit according to an embodiment of the present invention is shown.

[0025] Figure 2 A schematic diagram of the structure of the flexible actuator according to an embodiment of the present invention in a spreading form is shown.

[0026] Figure 3 A schematic diagram of the structure of the flexible actuator according to an embodiment of the present invention in a retracted form is shown.

[0027] Figure 4 A schematic diagram of the reconfigurable metasurface according to an embodiment of the present invention is shown.

[0028] Figure 5 A schematic diagram of the reconfigurable metasurface according to an embodiment of the present invention is shown when it is I-shaped;

[0029] Figure 6 A schematic diagram of the structure of the reconfigurable metasurface according to an embodiment of the present invention is shown.

[0030] The attached figures are labeled as follows:

[0031] 100 represents a metasurface unit;

[0032] 10 is a metal response layer, 20 is a flexible actuator, 30 is a dielectric layer, 40 is a drive control unit, 41 is a metal electrode, 42 is a drive control device, and 50 is a metal reflective layer. Detailed Implementation

[0033] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0034] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0035] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0036] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0037] See Figures 1 to 3 As shown, an embodiment of the present invention provides a metasurface unit 100, including a metal reflective layer 50, a dielectric layer 30, a flexible actuator 20, a metal response layer 10, and a drive control unit 40. The dielectric layer 30 covers one side of the metal reflective layer 50. Multiple flexible actuators 20 are fixed in a two-dimensional array on the side of the dielectric layer 30 away from the metal reflective layer 50. Each flexible actuator 20 has two forms: spreading and contracting. When two adjacent flexible actuators 20 are in the spreading form, they are interconnected.

[0038] A metallic responsive layer 10 covers the side of the flexible actuator 20 away from the dielectric layer 30. A drive control unit 40 is electrically connected to each flexible actuator 20 and is used to control each flexible actuator 20 to convert to an unfolded or contracted state.

[0039] According to the metasurface unit 100 of the present invention, by providing flexible actuators 20 in the metasurface unit 100, and the flexible actuators 20 being electrically connected to the drive control unit 40, the drive control device 42 can individually control each flexible actuator 20 to convert to an unfolding or contracting state. Therefore, independent control of each flexible actuator 20 can be achieved. When two adjacent flexible actuators 20 are in an unfolding state, the two adjacent flexible actuators 20 are interconnected. Conversely, when adjacent flexible actuators 20 are in a contracting state, the two adjacent flexible actuators 20 are not interconnected. In this way, the metasurface unit 100 can independently realize multiple structural forms. Therefore, the metasurface unit 100 has higher degrees of freedom, wider reconfigurable bandwidth, and more flexible and controllable electromagnetic wave manipulation capabilities.

[0040] It is understandable that the drive control unit 40 controls each flexible actuator 20 to be in an extended or retracted state. At this time, the flexible actuators 20 in the extended state are interconnected, and the interconnected flexible actuators 20 can form different configurations. In this way, the metasurface unit 100 can exhibit rich structural features, thereby realizing real-time response to electromagnetic waves of different microwave frequency bands, and has many potential applications in beamforming and electromagnetic stealth.

[0041] In some embodiments, the flexible actuator 20 can be cross-shaped, with the bottom center of the cross shape fixed to the dielectric layer 30, but the rest of the flexible actuator 20 is separate from the dielectric layer 30. This allows for either a spreading or contracting configuration, where the spreading configuration is as follows: Figure 2 As shown, the contraction pattern is as follows Figure 3 As shown. When the flexible actuator 20 is cross-shaped and in the contracted state, the four cross-shaped structures of the flexible actuator 20 contract inward (as shown). Figure 3 As shown), the two flexible actuators 20 are not connected at this time. When the flexible actuator 20 is cross-shaped and in a spread-out state, the cross-shaped structure of the flexible actuator 20 spreads on the dielectric layer 30 (as shown). Figure 2 As shown, when two adjacent flexible actuators 20 are in a spread-out state, the two adjacent flexible actuators 20 are interconnected. In this way, the metasurface unit 100 can have a variety of configurations, namely, higher degrees of freedom, wider reconfigurable bandwidth, and more flexible and controllable electromagnetic wave manipulation capabilities.

[0042] It is understandable that the flexible actuator 20 is made of ionically electroactive polymers, liquid crystal elastomers, shape memory polymers, or hydrogels.

[0043] Ionic electroactive polymers are dielectric elastomers, possessing advantages such as greater strain capacity, light weight, high driving efficiency, and good shock resistance. Examples of ionic electroactive polymers include carbon nanotubes (CNTs), conductive polymers (CP), electrorheological fluids (ERF), ionomer gels (IPG), and ionomer-based metal composites (IPMC). Ionic electroactive polymers consist of two electrodes and an electrolyte. Ion migration or dispersion can excite these materials at relatively low voltages (1–2V), inducing bending displacement.

[0044] When a liquid crystal elastomer is subjected to mechanical force, light, electric field, magnetic field, and temperature, the orientation of its internal liquid crystal cells changes, which appears as deformation on a macroscopic scale. However, when these forces are removed, the liquid crystal elastomer returns to its previous state, exhibiting a memory function.

[0045] Shape memory polymers are polymeric materials that, after a product with an initial shape is altered and fixed under certain conditions, can recover its initial shape through external stimuli such as heat, electricity, light, or chemical induction.

[0046] Hydrogels are a type of polymeric gel that can sense minute changes or stimuli in the external environment, such as temperature, pH, light, electricity, and pressure, and can produce corresponding changes or even mutations in their physical structure and chemical properties.

[0047] In some embodiments, the material of the metal response layer 10 is liquid metal or a metal sputtered film. Liquid metal has a universal deformability that can switch between different shapes and motion modes. The metal sputtered film is formed by bombarding the surface of the flexible actuator 20 with metal ions or molecules of a certain energy through a sputtering process, so that the atoms or molecules on the surface of the flexible actuator 20 obtain sufficient energy and eventually escape from the solid surface.

[0048] Specifically, the liquid metal is a gallium indium tin alloy, which not only has electrical conductivity but also excellent heat dissipation.

[0049] Specifically, liquid metal is coated onto the flexible actuator 20 using a screen printing method. The steps for coating the flexible actuator 20 with liquid metal using the screen printing method are as follows:

[0050] The first step is to stretch the wire mesh. Place the aluminum alloy wire mesh frame to be stretched horizontally on the ground and clamp the stretching tool. Apply wire mesh adhesive to the upper surface of the frame. After 3 to 5 minutes, align the warp and weft directions of the wire mesh with the frame, then use the stretching tool to tighten the wire mesh. Wait about 1 hour. Once the adhesive is completely dry, remove the mesh and store it in a ventilated place for 1 day before use.

[0051] The second step is to create the positive plate. Methods for creating positive plates include tracing, engraving, and photolithography. Tracing and engraving are manual plate-making methods, while photolithography is the main method for modern screen printing plate making. In this embodiment, the plate is made of monochrome lines; therefore, a computer-aided design laser printer is used to output the image onto a transparent film to create the positive plate. Modern ordinary laser printers can achieve a printing resolution of up to 720 dpi (less than the resolution of the human eye), which can produce positive plates with extremely small electrodes.

[0052] The third step is to apply the photosensitive emulsion. Prepare the photosensitive emulsion in a darkroom, stir well, and remove all bubbles before use. Use a clean brush dipped in a solution of detergent to clean both sides of the screen. Rinse with tap water until no bubbles remain, and dry with cold air. In a darkroom, apply the photosensitive emulsion using a glue applicator. Lean the screen frame against a wall with the screen facing outwards. Hold both ends of the applicator with both hands and apply the emulsion from top to bottom. The emulsion will slowly flow downwards under gravity. After some emulsion has flowed off, invert the screen frame to distribute the emulsion evenly. Then, quickly place the screen face up on the rack of the oven and dry with cold air.

[0053] The fourth step is screen printing. Take a piece of acrylic sheet with a thickness similar to the screen frame but slightly smaller than the inner edge of the frame. After washing and drying, place the printed positive film, printed side up, in the center and secure it with transparent tape. Ensure the images completely overlap. Place the acrylic sheet, plate side up, in the center of the glass plate in the printing box. In the darkroom, place the screen frame coated with photosensitive emulsion, emulsion side up, on top of the acrylic sheet. Add a flat, heavy object to ensure the emulsion side is firmly attached to the positive film. Then cover the printing box with a black cloth to prevent ultraviolet light from penetrating. Then, power on the printing process. Figure 5 After a few minutes, remove the exposed wire mesh frame and proceed with the development process.

[0054] The fifth step is development. The exposed halftone frame is immersed in clean water in a darkroom and removed after 5 hours.

[0055] The sixth step is to harden the film. After developing, rinse the screen frame from the inside with tap water, place it in an oven to dry with cold air, and then place it on an exposure box to expose both sides for about 15 minutes each.

[0056] The seventh step is printing. Depending on the complexity of the electrodes being printed, printing can be divided into several steps. Taking the simplest three-electrode design as an example, the steps are: liquid metal, insulating layer, carbon counter electrode layer, carbon working electrode layer, and liquid metal electrode layer. After each step, the electrodes must be placed in an oven for at least 12 hours to dry before proceeding to the next step. After all printing is complete, the electrodes are dried in an oven for 24 hours, and then cut to size for use.

[0057] The reason for covering the flexible actuator 20 with liquid metal by screen printing is that screen printing requires simple equipment, requires less investment, and has the advantage of being able to produce inexpensive microelectrodes.

[0058] Understandably, the metal reflective layer 50 is made of copper, which can effectively suppress the transmission of electromagnetic waves.

[0059] It is understandable that the drive control unit 40 controls the flexible actuator 20 to change its form by voltage control, electrostatic control, temperature control, light control, or pH control.

[0060] In some embodiments, the drive control unit 40 controls the flexible actuator 20 to change form by voltage control. In this case, the drive control unit 40 includes a plurality of metal electrodes 41 and a drive control device 42. The drive control device 42 is electrically connected to the metal electrodes 41, and the metal electrodes 41 are individually connected to each flexible actuator 20.

[0061] See Figure 1 As shown, metal electrodes 41 are inserted into the dielectric layer 30 and connected to the drive control device 42 via wires. Specifically, the drive control device 42 can be an FPGA chip. Metal electrodes 41 are also directly connected to the flexible actuator 20, which is made of an ionoactive polymer. The FPGA chip stores circuit control strategies for different response states. When the structure of the metasurface unit 100 needs to be changed, the FPGA chip controls the power supply to different metal electrodes 41. Each flexible actuator 20 corresponding to a metal electrode 41 undergoes physical deformation under the influence of current, voltage, or electric field. This physical deformation manifests as the flexible actuator 20 expanding or contracting.

[0062] When two adjacent flexible actuators 20 are in an extended state, they are connected to each other; when two adjacent flexible actuators 20 are in a contracted state, they are not connected.

[0063] It is understandable that when the flexible actuator 20 is in its initial state, that is, when no voltage is applied, the flexible actuator 20 is in a contracted state. When the metal electrode 41 corresponding to the flexible actuator 20 is energized, the flexible actuator 20 is in an extended state under the influence of the voltage.

[0064] In some embodiments, the drive control unit 40 controls the flexible actuator 20 to change form by temperature control. In this case, the drive control unit 40 includes a plurality of metal electrodes 41 and a drive control device 42. The drive control device 42 is electrically connected to the metal electrodes 41, and the metal electrodes 41 are individually connected to each flexible actuator 20.

[0065] Metal electrodes 41 are inserted into the dielectric layer 30 and connected to the drive control device 42 via wires. Specifically, the drive control device 42 can be an FPGA chip. Metal electrodes 41 are also directly connected to the flexible actuator 20, which is made of liquid crystal elastomer. The FPGA chip stores circuit control strategies for different response states. When the structure of the metasurface unit 100 needs to be changed, the FPGA chip controls the power supply to different metal electrodes 41. The metal electrodes 41 change temperature due to the current, causing the flexible actuator 20 to undergo physical deformation. This physical deformation manifests as the flexible actuator 20 expanding or contracting.

[0066] In some embodiments, the driving control unit 40 controls the flexible driver 20 to transform its shape in a light control manner. At this time, the driving control unit 40 includes a plurality of diodes and a driving control device 42. The driving control device 42 is electrically connected to the diodes, and each diode is individually connected to each flexible driver 20. Specifically, the driving control device 42 can be an FPGA chip. The diodes are connected to the flexible driver 20, and the material of the flexible driver 20 at this time is liquid crystal elastomer. Different circuit control strategies in different response states are stored in the FPGA chip. When it is necessary to change the structure of the metasurface unit 100, the FPGA chip controls the power supply to different diodes. The diodes are in two states of emitting light or not emitting light, so the flexible driver 20 also undergoes two physical shape changes. At this time, the physical deformation is reflected as the flexible driver 20 being in a spread shape or a contracted shape.

[0067] In some embodiments, the driving control unit 40 controls the flexible driver 20 to transform its shape in a pH control manner. At this time, the driving control unit 40 includes a plurality of transfer tubes and a driving control device 42. The driving control device 42 is electrically connected to the transfer tubes, and each transfer tube is individually connected to each flexible driver 20. The transfer tubes deliver the control solution to the flexible driver 20. Specifically, the driving control device 42 can be an FPGA chip. The transfer tubes are connected to the flexible driver 20, and the material of the flexible driver 20 at this time is shape memory polymer. Different circuit control strategies in different response states are stored in the FPGA chip. When it is necessary to change the structure of the metasurface unit 100, the FPGA chip controls the control solution to be delivered to different transfer tubes. The transfer tubes deliver the control solution to the flexible driver 20, and the shape memory polymer undergoes deformation due to chemical induction. Therefore, the flexible driver 20 undergoes two physical shape changes. At this time, the physical deformation is reflected as the flexible driver 20 being in a spread shape or a contracted shape.

[0068] Refer to Figures 4 to 6 As shown, in this embodiment, a reconfigurable electromagnetic metasurface is also provided. The reconfigurable electromagnetic metasurface includes a plurality of the above-mentioned metasurface units 100.

[0069] Specifically, the reconfigurable electromagnetic metasurface is composed of a 9*9 uniformly arranged array of flexible drivers 20. Specific flexible drivers 20 are interconnected through the spread shape, so the reconfigurable electromagnetic metasurface presents different electromagnetic response structures, thus achieving the reconfigurable effect.

[0070] The configuration of the reconfigurable electromagnetic metasurface can be a cross shape (as shown in Figure 4 ), a shape similar to the Chinese character "工" (as shown in Figure 5 ), and a Jerusalem cross shape (as shown in Figure 6 ).

[0071] Among them, Figures 4 to 6 The connected flexible actuators 20 are in an extended state, while the unconnected flexible actuators 20 are in a contracted state.

[0072] According to this embodiment, the reconfigurable electromagnetic metasurface includes metasurface units 100. Each metasurface unit 100, through a drive control unit 40, can achieve independent control of each flexible actuator 20. Therefore, the reconfigurable electromagnetic metasurface unit 100 can independently realize multiple structural forms, enabling dynamic and flexible adjustment of the reconfigurable electromagnetic metasurface and satisfying the high-degree-of-freedom real-time adjustment capability of the reconfigurable electromagnetic metasurface.

[0073] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A metasurface unit, characterized in that, The super surface unit comprises: a metal reflecting layer; a dielectric layer covering one side of the metal reflecting layer; a plurality of flexible actuators fixed in a two-dimensional array on the side of the dielectric layer away from the metal reflecting layer, the flexible actuators having an expanded state and a contracted state, two adjacent flexible actuators being in communication with each other when in the expanded state, and not in communication with each other when one of the two adjacent flexible actuators is in the contracted state, the flexible actuators in communication with each other being capable of forming different configurations; a metal responsive layer covering the side of the flexible actuators away from the dielectric layer, wherein the metal responsive layer is a metal sputtering film, and atoms or molecules on the surface of the flexible actuators escape from the surface to form the metal sputtering film; a driving control unit electrically connected to each of the flexible actuators, the driving control unit being configured to control each of the flexible actuators to switch between the expanded state and the contracted state, wherein the driving control unit controls the flexible actuators to switch between the expanded state and the contracted state by voltage control, and the driving control unit comprises a plurality of metal electrodes and a driving control device, the driving control device being electrically connected to the metal electrodes, and each of the metal electrodes being connected to a corresponding flexible actuator.

2. The metasurface unit of claim 1, wherein, The flexible actuators are in the shape of a cross, and the bottom center of each of the flexible actuators is fixed to the dielectric layer.

3. The metasurface unit of claim 1, wherein, The material of the flexible actuators is ionically electroactive polymers, liquid crystal elastomers, shape memory polymers, or hydrogels.

4. The metasurface unit of claim 1, wherein, The material of the metal responsive layer is a liquid metal or a metal sputtering film.

5. The metasurface unit of claim 4, wherein, The liquid metal is a gallium-indium-tin alloy.

6. The metasurface unit of claim 4, wherein, The liquid metal is applied to the flexible actuators by a screen printing method.

7. The metasurface unit of claim 1, wherein, The material of the metal reflecting layer is copper.

8. A reconfigurable electromagnetic metasurface, characterized in that, The super surface unit comprises the super surface unit according to any one of claims 1-7.

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