Electromagnetic metasurface device and method of manufacture

Abstract

The electromagnetic metasurface device and the preparation method provided by the application comprise a metasurface structure unit array layer and an auxiliary layer, a plurality of microfluidic channels for flowing working liquid are arranged on the metasurface structure unit array layer, and a metasurface structure unit is arranged on any microfluidic channel, the auxiliary layer comprises an encapsulation layer, the encapsulation layer comprises an upper encapsulation layer and a lower encapsulation layer, and the metasurface structure unit array layer is mounted between the upper encapsulation layer and the lower encapsulation layer. The electromagnetic metasurface device and the preparation method provided by the application apply liquid metal materials in the design of reconfigurable metasurface electromagnetic devices, and by reasonably designing the microfluidic channel structure of a microfluidic chip in combination with microfluidic technology, the shape and size of the liquid metal can be changed as required, the performance reconfiguration of ultrawideband and multi-state can be realized, and different functional requirements of the device in complex application scenarios can be met in real time.

Description

Technical Field

[0001] The present application belongs to the technical field of artificial electromagnetic materials, and specifically relates to an electromagnetic metasurface device and a preparation method thereof. Background Art

[0002] Electromagnetic metasurfaces, also known as artificial electromagnetic surfaces, are essentially equivalent to two-dimensional artificial metamaterials with negligible longitudinal thickness. These ultrathin surfaces are composed of subwavelength metamaterial units that are periodically or quasi-periodically extended in the lateral dimension. They exhibit low loss and conformality. By rationally designing the metasurface unit topography and array arrangement, comprehensive control of electromagnetic waves can be achieved. Early metasurfaces primarily employed periodic arrangements of identically structured units, such as frequency selective surfaces, electromagnetic band gaps, polarization gratings, and artificial magnetic conductors.

[0003] Because the structures and functions of these metasurface electromagnetic devices are relatively fixed, using only a single device often makes it difficult to meet the diverse demands for electromagnetic wave control. In recent years, reconfigurable electromagnetic metasurfaces have emerged. Classic reconfiguration methods primarily employ tuning devices such as varactor diodes, PIN diodes, and microelectromechanical system switches, or mechanical stretching and rotation, often using solid metals and dielectric materials. This paper explores a new reconfiguration mechanism to enhance the reconfigurability of electromagnetic metasurfaces. Summary of the Invention

[0004] The present invention provides a reconfigurable electromagnetic metasurface device based on liquid metal and microfluidic technology and a preparation method thereof.

[0005] This application adopts the following technical solutions:

[0006] One of the purposes of the present application is to provide an electromagnetic metasurface device, comprising a metasurface structure unit array layer and an auxiliary layer, wherein the metasurface structure unit array layer is provided with a plurality of microfluidic channels for the flow of working fluid, and a metasurface structure unit is arranged on any of the microfluidic channels, the auxiliary layer comprises a packaging layer, the packaging layer comprises an upper packaging layer and a lower packaging layer, and the metasurface structure unit array layer is installed between the upper packaging layer and the lower packaging layer.

[0007] In some embodiments, the shapes of the several microfluidic channels are the same or different.

[0008] In some embodiments, the plurality of microfluidic channels are independent of each other and not interconnected.

[0009] In some embodiments, the working liquid includes liquid metal, and the liquid metal is a gallium-indium-tin alloy.

[0010] In some embodiments, the working liquid further includes a lubricating liquid that is non-wetting with the liquid metal, and the lubricating liquid includes but is not limited to dimethyl silicone oil.

[0011] In some embodiments, the metasurface structure unit is a spiral, linear, broken line, or open ring structure and various derivative forms thereof.

[0012] In some embodiments, an isolation layer and a guide layer are sequentially arranged between the metasurface structure unit array layer and the lower packaging layer, the isolation layer is provided with a through-hole structure, and the guide layer is provided with a microchannel structure.

[0013] In some embodiments, the upper packaging layer, the metasurface structure unit array layer, the isolation layer, the guide layer and the lower packaging layer are bonded with pressing adhesive, and a certain pressure is applied to expel bubbles in the non-channel area to ensure the bonding quality between the layers.

[0014] In some embodiments, the upper packaging layer is further provided with a through hole.

[0015] A second object of the present application is to provide a method for preparing an electromagnetic metasurface device, comprising the following steps:

[0016] Pre-treating a substrate, wherein the substrate comprises an organic glass plate or a polyimide film;

[0017] The super-surface structure unit array layer is processed on the surface of the substrate using micro-machining technology, and a plurality of microfluidic channels for the flow of working liquid are provided on the super-surface structure unit array layer, and a super-surface structure unit is arranged on any of the microfluidic channels;

[0018] The metasurface structure unit array layer is installed between the upper packaging layer and the lower packaging layer, and the upper packaging layer and the lower packaging layer are both obtained by processing the substrate.

[0019] In some embodiments, the following steps are also included:

[0020] introducing dimethyl silicone oil into any one of the microfluidic channels for surface pretreatment;

[0021] The liquid metal is sealed with a sodium hydroxide solution in an oxygen-free environment to remove the oxide layer on the surface of the liquid metal;

[0022] An electronic syringe pump is used to sequentially and cyclically extract a working liquid of a segmented combination of liquid metal and sodium hydroxide solution in the microfluidic channel;

[0023] The microfluidic channel filled with working liquid is installed in the corresponding hole position of the upper packaging layer and sealed.

[0024] This application adopts the above technical solution to achieve the following effects:

[0025] The electromagnetic metasurface device and preparation method provided in the present application include a metasurface structure unit array layer and an auxiliary layer. A plurality of microfluidic channels for the flow of working fluid are arranged on the metasurface structure unit array layer, and a metasurface structure unit is arranged on any of the microfluidic channels. The auxiliary layer includes a packaging layer, and the packaging layer includes an upper packaging layer and a lower packaging layer. The metasurface structure unit array layer is installed between the upper packaging layer and the lower packaging layer. In the electromagnetic metasurface device and preparation method provided in the present application, the liquid metal has many characteristics such as high conductivity, good fluidity, and controllable deformation. By applying liquid metal materials to the design of reconfigurable metasurface electromagnetic devices and combining them with microfluidic technology to rationally design the microfluidic channel structure of the microfluidic chip, the shape and size of the liquid metal can be changed on demand, enabling ultra-wideband and multi-state performance reconfiguration, ensuring that the device meets different functional requirements in real time under complex application scenarios; secondly, liquid metal does not have the nonlinear characteristics of control elements, it has high power capacity and can meet the power requirements of more electronic systems; in addition, by designing liquid metal microfluidic channels using flexible materials such as polydimethylsiloxane and polyimide film, conformable electromagnetic devices can be designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 Schematic diagram of the layered structure of the electromagnetic metasurface device according to Example 1 of the present invention;

[0028] Figure 2 Schematic diagram of various working states of the electromagnetic metasurface device according to Example 1 of the present invention;

[0029] Figure 3 Schematic diagram of the layered structure of the electromagnetic metasurface device according to Example 2 of the present invention;

[0030] Figure 4 Schematic diagram of the cross-sectional structure of the electromagnetic metasurface device according to embodiment 2 of the present invention;

[0031] Figure 5 Schematic diagram of various working states of the electromagnetic metasurface device according to Example 2 of the present invention;

[0032] Figure 6Schematic diagram of the preparation process of the electromagnetic metasurface device provided in Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0033] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0036] Example 1

[0037] See also Figure 1 , which is a schematic structural diagram of an electromagnetic metasurface device provided in an embodiment of the present application, comprising: a metasurface structure unit array layer 2 and an auxiliary layer 10. The specific implementation scheme of each layer is described in detail below.

[0038] A plurality of microfluidic channels for the flow of working liquid are provided on the metasurface structure unit array layer 1 , and a metasurface structure unit 5 is arranged on any of the microfluidic channels.

[0039] Specifically, the shapes of the several microfluidic channels are the same or different.

[0040] Furthermore, the plurality of microfluidic channels are independent of each other and not interconnected.

[0041] It can be understood that the microfluidic channel can be controlled individually or in combination, that is, an external control device such as a high-precision electronic injection pump and its supporting pipelines can accurately control the flow rate and flow rate of the working liquid in the microfluidic channel.

[0042] Specifically, the super surface structure unit 5 is a spiral, straight, broken line, or open ring structure and various derivative forms thereof.

[0043] It can be understood that the metasurface structure unit 5 of the microfluidic channel determines the size, shape, and arrangement of the metal microstructure. According to subwavelength electromagnetic theory, different subwavelength metal microstructures have corresponding resonant operating frequencies and impedance matching characteristics, which can effectively control the amplitude, polarization, phase, and other physical parameters of the electromagnetic wave. The metasurface structure unit 5 can be set to a spiral shape, a broken line shape, an open ring structure, and various derivative or combined forms to meet different electromagnetic wave control function requirements. Specifically, the working liquid includes liquid metal, a segmented mixture of liquid metal and other liquids, dimethyl silicone oil lubricant, and other liquid substances necessary to ensure the normal operation of the device. The liquid metal is a gallium indium tin alloy.

[0044] Liquid metal, understandably, combines the excellent properties of solid metal and fluid dielectric materials, possessing both electrical conductivity and fluidity. Gallium-indium-tin alloys are suitable for the fabrication of various electromagnetic devices for the following reasons: first, their low viscosity and excellent fluidity facilitate injection into microfluidics; second, their excellent electrical conductivity, far exceeding that of other conductive liquids; third, their stable performance and low volatility; and fourth, their lack of biotoxicity, ensuring the safety and reliability of the devices.

[0045] Furthermore, the microfluidic channel is also pre-filled with a lubricating liquid that does not wet the liquid metal, and the lubricating liquid includes but is not limited to dimethyl silicone oil.

[0046] The packaging layer 10 includes an upper packaging layer 1 and a lower packaging layer 3 , and the metasurface structure unit array layer is installed between the upper packaging layer 1 and the lower packaging layer 3 .

[0047] Furthermore, a through hole 4 is provided on the upper packaging layer 1 .

[0048] It can be understood that under the action of the through hole 4, the upper packaging layer 1, the metasurface structure unit array layer and the lower packaging layer 3 are bonded with a surface adhesive, and a certain pressure is applied to expel bubbles in the non-channel area to ensure the bonding quality between the layers. The electromagnetic metasurface device provided in the above embodiment 1 of the present application adopts liquid metal microfluidic technology. The flow rate and flow direction of the working liquid in each microfluidic channel are controlled by a high-precision electronic injection pump. The position and shape of the working liquid in the microfluidic channel can be accurately controlled, thereby realizing the continuous and real-time reconfiguration of the working state and performance of the electromagnetic metasurface device. Several working states of the device, such as Figure 2 As shown, the black part in the microfluidic channel is liquid metal and the white part is sodium hydroxide solution.

[0049] In this embodiment, polyimide film is used as the material to process the electromagnetic metasurface device, which can be attached to various surfaces to meet various conformal application requirements.

[0050] Example 2

[0051] See also Figure 3 and Figure 4 , which is a schematic structural diagram of the electromagnetic metasurface device provided in Example 2 of the present application. The difference from Example 1 is that the auxiliary layer further includes an isolation layer 3 and a guide layer 4 disposed between the metasurface structure unit array layer 2 and the lower packaging layer 5. The isolation layer 4 is provided with a through-hole structure 5, and the guide layer 4 is provided with a microchannel structure 9.

[0052] Furthermore, the upper packaging layer 1, the metasurface structure unit array layer 2, the isolation layer 3, the guide layer 4 and the lower packaging layer 5 are bonded with a pressing adhesive, and a certain pressure is applied to expel bubbles in the non-channel area to ensure the bonding quality between the layers.

[0053] In this embodiment, the microfluidic channel is arranged with supersurface structural units 7, and the shape of the structural units is a spiral structure. Different from Example 1, due to the particularity of the shape of the resonance unit of this embodiment, the microfluidic channels connecting the various structural units are not on the same layer as the structural units. Figure 4 A schematic cross-sectional view of the structure of this embodiment is shown to illustrate the flow of the working liquid between the layers of the device. In this embodiment, the material of each layer is a 0.5 mm thick organic glass plate.

[0054] It can be understood that by applying pressure through a high-precision electronic syringe pump to drive the working liquid in each microfluidic channel, different working states can be achieved. By changing the mixing ratio of liquid metal and sodium hydroxide solution in the pipeline, each structural unit can be independently controlled in this embodiment. Figure 5 Six different working states are listed. Figure 5 The black part in the middle represents liquid metal, the gray part represents the base material, and the white part is sodium hydroxide solution.

[0055] Example 3

[0056] See also Figure 6 , is a flowchart of a method for preparing an electromagnetic metasurface device provided in Example 3 of the present application, comprising the following steps:

[0057] Step S110: pre-treating a substrate, wherein the substrate includes an organic glass plate or a polyimide film.

[0058] Specifically, the materials to be processed are pre-treated by cutting and gluing. A 0.05mm thick polyimide film is used as the conformal material, while a 0.5mm thick plexiglass sheet is used as the conventional material. These materials are cut to the appropriate size and then laid out and fixed on a horizontal ceramic workbench. The surface to be processed is then evenly glued with a 0.2mm thick adhesive. Pressure is applied to eliminate bubbles and ensure a perfect fit.

[0059] Step S120: using micromachining technology to process the super surface structure unit array layer on the surface of the substrate, and setting a plurality of microfluidic channels for the flow of working liquid on the super surface structure unit array layer, and any one of the microfluidic channels is arranged with a super surface structure unit.

[0060] Specifically, when using a carbon dioxide laser engraving machine to process the microstructure of the metasurface structure unit array layer and the auxiliary layer, it is necessary to adjust the processing speed and processing power, strictly control the thermal warping deformation of the material during the processing, and ensure the processing quality.

[0061] Step S130: installing the metasurface structure unit array layer between the upper packaging layer and the lower packaging layer, wherein the upper packaging layer and the lower packaging layer are both processed from the substrate.

[0062] It can be understood that when completing the bonding and assembly of each layer, it is important to apply a certain external force when bonding each layer to eliminate bubbles between layers. If the bubbles are not eliminated layer by layer during the assembly process, the bubbles will be difficult to remove when the assembly is completed, affecting the normal operation of the device.

[0063] Furthermore, the method for preparing the electromagnetic metasurface device further includes the following steps:

[0064] Step S140: Dimethyl silicone oil is introduced into any one of the microfluidic channels for surface pretreatment.

[0065] Dimethyl silicone oil is introduced into the above-mentioned multiple microfluidic channels for surface pretreatment. The purpose is to form a hydrophobic oil film on the inner wall of the microfluidic channel, improve the quality of the processed surface, facilitate the smooth flow of liquid metal in the channel, and reduce the inner wall residue during the reconstruction process.

[0066] Step S150: sealing the liquid metal with a sodium hydroxide solution in an oxygen-free environment to remove the oxide layer on the surface of the liquid metal;

[0067] Step S160: using an electronic syringe pump to sequentially and cyclically extract a working liquid of a segmented combination of liquid metal and sodium hydroxide solution in the microfluidic channel;

[0068] It can be understood that by using an electronic injection pump to adopt a sequential and quantitative extraction method, a working liquid composed of liquid metal and sodium hydroxide solution in a certain proportion is formed in the pipeline. The working liquid can be stored in the pipeline, which reduces the complexity of chip design. In addition, the diversification of reconfigurable states can be achieved by adjusting the ratio between the components of the working liquid.

[0069] Step S170: Install the microfluidic channel filled with the working liquid in the corresponding hole position of the upper packaging layer to achieve sealed installation.

[0070] In the preparation method of electromagnetic metasurface devices provided in this application, liquid metal has many characteristics such as high conductivity, good fluidity, and controllable deformation. By applying liquid metal materials to the design of reconfigurable metasurface electromagnetic devices, combined with microfluidic technology and rationally designing the microfluidic channel structure of the microfluidic chip, the shape and size of the liquid metal can be changed on demand, enabling ultra-wideband and multi-state performance reconfiguration, ensuring that the device meets different functional requirements in real time under complex application scenarios. Secondly, liquid metal has high power capacity and can meet the power requirements of more electronic systems. In addition, by designing liquid metal microfluidic channels using flexible materials such as polydimethylsiloxane and polyimide films, conformable electromagnetic devices can be designed.

[0071] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. An electromagnetic metasurface device, characterized in that: The invention comprises a metasurface structure unit array layer and an auxiliary layer, wherein the metasurface structure unit array layer is provided with a plurality of microfluidic channels for the flow of a working liquid, and a metasurface structure unit is arranged on any of the microfluidic channels, the working liquid comprises liquid metal, the auxiliary layer comprises an encapsulation layer, the encapsulation layer comprises an upper encapsulation layer and a lower encapsulation layer, and the metasurface structure unit array layer is installed between the upper encapsulation layer and the lower encapsulation layer; The plurality of microfluidic channels are independent of each other and not interconnected; The auxiliary layer further includes an isolation layer and a guide layer provided between the metasurface structure unit array layer and the lower packaging layer, wherein the isolation layer is provided with a through-hole structure, and the guide layer is provided with a microchannel structure; The super surface structural unit is spiral-shaped; The upper packaging layer is also provided with a through hole; The liquid metal is sealed with a sodium hydroxide solution in an oxygen-free environment to remove the oxide layer on the surface of the liquid metal; An electronic syringe pump is used to sequentially and cyclically extract a working liquid of a segmented combination of liquid metal and sodium hydroxide solution in the microfluidic channel; An electronic injection pump applies pressure to drive the working liquid in each microfluidic channel to achieve different working states. By changing the mixing ratio of liquid metal and sodium hydroxide solution in the pipeline, each structural unit can be independently controlled.

2. The electromagnetic metasurface device according to claim 1, characterized in that The liquid metal is a gallium-indium-tin alloy.

3. The electromagnetic metasurface device according to claim 2, characterized in that The working liquid further includes a lubricating liquid that does not wet the liquid metal, and the lubricating liquid includes but is not limited to dimethyl silicone oil.

4. The electromagnetic metasurface device according to claim 1, wherein: The upper packaging layer, the metasurface structure unit array layer, the isolation layer, the guide layer and the lower packaging layer are bonded together with a pressing adhesive, and a certain pressure is applied to expel bubbles in the non-channel area to ensure the bonding quality between the layers.

5. A method for preparing an electromagnetic metasurface device according to claim 1, characterized in that: The steps include: Pre-treating a substrate, wherein the substrate comprises an organic glass plate or a polyimide film; The super-surface structure unit array layer is processed on the surface of the substrate using micro-machining technology, and a plurality of microfluidic channels for the flow of working liquid are provided on the super-surface structure unit array layer, and a super-surface structure unit is arranged on any of the microfluidic channels; Installing the metasurface structure unit array layer between the upper packaging layer and the lower packaging layer, wherein the upper packaging layer and the lower packaging layer are both obtained by processing the substrate; The auxiliary layer further includes an isolation layer and a guide layer arranged between the metasurface structure unit array layer and the lower packaging layer. The isolation layer is provided with a through-hole structure, and the guide layer is provided with a microchannel structure.

6. The method for preparing an electromagnetic metasurface device according to claim 5, wherein: The following steps are also included: introducing dimethyl silicone oil into any one of the microfluidic channels for surface pretreatment; The liquid metal is sealed with a sodium hydroxide solution in an oxygen-free environment to remove the oxide layer on the surface of the liquid metal; An electronic syringe pump is used to sequentially and cyclically extract a working liquid of a segmented combination of liquid metal and sodium hydroxide solution in the microfluidic channel; The microfluidic channel filled with working liquid is installed in the corresponding hole position of the upper packaging layer to achieve sealed installation.

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