A high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude

Abstract

A high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude belongs to the fields of optically transparent electromagnetic shielding and microwave communication. This window consists of an electrically adjustable metasurface layer of integrated patterned phase change material and a transparent dielectric layer, arranged in parallel and overlapping layers. The electrically adjustable metasurface layer is composed of a periodically densely arranged array of electrically adjustable metasurface units of integrated patterned phase change material, and the edges of the electrically adjustable metasurface layer have metal electrodes and leads connected to the metal electrodes. This invention solves the problem that existing optical windows cannot simultaneously achieve high optical transparency over a wide wavelength range, adjustable microwave transmission amplitude, and fast response time.

Description

Technical Field

[0001] This invention belongs to the fields of optically transparent electromagnetic shielding and microwave communication, and specifically relates to a high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude. Background Technology

[0002] With the rapid development and application of technologies such as the Internet of Things (IoT) and 5G, the application of radio frequency (RF) and microwave technologies has experienced explosive growth, leading to an order-of-magnitude increase in devices capable of transmitting and receiving electromagnetic waves. The application bands of electromagnetic waves are constantly expanding, their intensity is continuously increasing, and the electromagnetic environment is becoming increasingly complex. While the widespread use of electromagnetic waves brings convenience to people's lives, it can also lead to unacceptable electronic system failures, and long-term exposure to complex electromagnetic environments can harm human health. In some applications, instruments and equipment not only need to shield certain frequency bands of electromagnetic waves but also need to allow some electromagnetic waves used for communication and detection to pass through. For example, in medical facilities such as intensive care units (ICUs) and cardiac care units (CCUs), communication is restricted to the spectrum below the C-band (4GHz-8GHz), where only 3G and 4G mobile connections are maintained. However, all high-frequency signals, such as the upper-layer WLAN band of 802.11ac WLAN and certain bands of ISM, need to be shielded. In applications such as aircraft, satellites, and ships, it is desirable to completely shield electromagnetic waves in interfering bands while allowing low-loss passage of electromagnetic waves used for communication and detection. Therefore, achieving effective shielding against electromagnetic interference and controlling the amplitude of electromagnetic wave transmission will be issues that must be considered in the future development of electronic devices.

[0003] To address this problem, electromagnetic shielding and frequency selective technologies have emerged, holding significant strategic importance in both the national economy and national defense. Electromagnetic shielding is primarily achieved through electromagnetic reflection and absorption, with commonly used methods including metal mesh, metal oxide thin films, and ITO utilizing electromagnetic reflection. A frequency selective surface (FSS) is a two-dimensional periodic array structure that can be designed with excellent frequency selectivity within the electromagnetically shielded band, enabling selective transmission of specific bands while providing electromagnetic shielding for other bands. Essentially, an FSS is a spatial filter, exhibiting distinct bandpass or bandstop filtering characteristics when interacting with electromagnetic waves. Aperture-type FSSs are widely used due to their significant bandpass near the resonant center frequency and out-of-band shielding suppression. Currently, FSSs are mainly divided into two categories: active and passive. The electromagnetic transmission characteristics of passive FSSs cannot be changed once designed, and their frequency selectivity is fixed, making it difficult to "turn off" or adjust them, thus failing to meet the requirements of complex environments. While tunable frequency selectivity surfaces formed by loading various active components have dynamic adjustable characteristics, their optical transmittance is low, making them unsuitable for applications requiring visual observation.

[0004] Currently, achieving both high optical transmittance and electromagnetic wave control has become a challenging and hot topic in the field of electromagnetic shielding, such as in automotive windows, optical instrument windows and display panels, windows in electromagnetic isolation rooms and security facilities, transparent components in communication equipment, and mobile phone touchscreens. Developing transparent devices with continuously adjustable transmission amplitudes has a very broad application prospect in these fields.

[0005] In the field of transparent frequency selective surfaces, patents 202210731684.7 and 201510262958.2 both utilize a metal mesh grid-encapsulated array of frequency selective surfaces to construct a transparent frequency selective surface, which can simultaneously achieve optical transparency and selective electromagnetic wave shielding. Patent 202221287914.7 utilizes a metal mesh grid-encapsulated top loss layer and bottom frequency selective surface to achieve an optically transparent, low-loss, integrated absorption and transmission frequency selective surface. Patent 202123073767.1 discloses a high-transmittance frequency selective surface structure, which consists of a transparent cover plate, a transparent low-frequency absorbing layer, and a transparent high-frequency transmitting layer stacked sequentially, enabling optically transparent frequency selective transmission. However, once the above structures are manufactured, their electromagnetic transmission characteristics cannot be changed, failing to meet the requirements of adjustable applications.

[0006] In the field of tunable frequency selective surfaces, patents 202111320455.8, 201810905959.8, and 201410428210.0 combine varactor diodes with resonant units, changing the capacitance of the varactor diode by applying an external bias voltage, thereby achieving continuous tunability of the stopband in a specific frequency band. However, the inherent opacity of metals prevents their use in the optical field, and the opacity of the varactor diode and the complex feeding network mean that even if the metal part is made transparent, the overall structure cannot be made transparent. In addition, the combination of varactor diodes and resonant units, when applied to optical window materials, also presents problems such as difficulty in soldering the diodes and easy detachment, and the frequency limitation of the diodes themselves makes it difficult for the structure to operate at high frequencies.

[0007] Besides using lumped elements to achieve adjustable functionality, another method is to load actively controlled materials, such as graphene, liquid crystals, and phase change materials. Patents 202011498478.3 and 202110243533.2 utilize optically transparent tunable absorbers composed of graphene and ITO, both consisting of multi-layered structures (ten or eleven layers). The absorption frequency is adjusted by controlling the sheet resistance of the graphene. However, the excessive number of layers leads to poor optical transparency of the final overall structure and limits its application areas. The use of ITO makes it difficult for the absorber to achieve wide-band optical transparency. Controlling graphene by applying an external voltage is complex and also affects light transmission. Furthermore, these structural designs typically only allow adjustment of absorption strength with almost no transmission, failing to achieve tuning of transmission characteristics. Patents 202010638683.9 and 202011251647.3 combine liquid crystal materials with metal structures, adjusting the dielectric constant of the liquid crystal material by applying a voltage, thereby achieving the tuning capability of the overall structure. However, due to the limited tuning range of the dielectric constant of liquid crystals, a complex multilayer structure design is required to achieve a suitable tuning range. This design is not only complex, but the poor transparency of liquid crystals themselves further exacerbates the problem. Introducing a multilayer structure results in very poor overall optical transparency, making it unsuitable for optical transparency applications. Liquid crystal-based tuning methods suffer from narrow tuning ranges and poor electromagnetic shielding capabilities outside the passband, making them difficult to apply to transparent electromagnetic shielding. Patent 202011136561.6 discloses a high-transmittance microwave absorption window with an electrically adjustable reflection band, assembled from sequentially overlapping and parallel graphene layers, a transparent dielectric layer, an electrically controllable tunable frequency-selective surface layer integrating phase change material, a transparent dielectric layer, and a metal mesh layer. This window simultaneously achieves high optical transparency, tunable reflection band, and out-of-band suppression of the reflection band, primarily through absorption. However, its essence is to indirectly heat the phase change material by heating the frequency selective surface connected to the phase change material with an electric current, thus causing the phase change to occur, rather than directly achieving the phase change of the phase change material through electronic control. Patent 202210110004.X also proposes a high-transmittance, thermally tunable microwave absorption window based on a thermally induced phase change material, which is also a temperature-controlled adjustment method. The control response time of this type of method is relatively long, and the temperature control requires the ambient temperature to remain almost constant to prevent the electromagnetic properties from becoming tunable prematurely when no tunability is needed, which seriously limits its practical application. At the same time, these two types of windows can only achieve tunability of absorption / reflection properties, and cannot tune transmission properties. Patent 202011121522.9 discloses a microwave transmission passband tunable high-transmittance window composed of a patterned graphene layer, a transparent dielectric layer, and a frequency selective surface layer of integrated phase change material. It achieves the ability to achieve high optical transparency and tunable transmission passband.However, it also uses temperature to induce phase change in phase materials, so its control response time is relatively long. Its actual use is limited by the temperature of the application environment. Furthermore, the presence of the graphene layer leads to a large passband loss in the transmission passband of the entire structure, which cannot achieve good results in situations where electromagnetic wave transmission is required, thus limiting its application range.

[0008] The phase change materials mentioned in the aforementioned patents exhibit reversible changes in material properties under external stimulation. Vanadium dioxide, in particular, can undergo a phase transition at room temperature through external stimulation (Joule heating, electric fields, magnetic fields, stress, and optical fields, etc.). Its theoretical conductivity, with an adjustable range of nearly five orders of magnitude before and after the phase transition, has attracted considerable attention. Patents such as 202110465365.1, 202110497432.8, 202010331974.3, 202011261049.4, 202022308742.4, 201821278319.0, 201821438858.6, 201821446265.4, 201821907011.8, 201920654141.3, and 201921357422 are relevant examples. 9. Patents such as 201921357423.3 and 201921831563.X are all tunable absorbers based on vanadium dioxide. However, these patents usually contain a metal reflective layer, and the vanadium dioxide pattern has a large occupancy ratio, resulting in opacity or poor transparency in the optical band, making them unsuitable for optically transparent applications. In addition, these patents are designed for the modulation of absorption performance, and the absorption performance is not directly related to the transmission performance, so they cannot be used to control the amplitude of microwave transmission.

[0009] In summary, existing transparent frequency-selective surfaces and tunable electromagnetic wave technologies struggle to simultaneously achieve high optical transparency across a wide wavelength range, tunable transmission amplitude, and rapid response tuning. Optically transparent frequency-selective surfaces typically have fixed electromagnetic transmission performance once the device is fabricated, making real-time adjustment impossible. Tunable electromagnetic wave structures with lumped elements suffer from problems such as requiring complex bias networks, difficulty in bonding with transparent dielectric materials, and poor or no light transmittance. Tunable structures with actively controlled materials exhibit complex control methods, slow response speeds, and high passband losses. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing transparent frequency selective surfaces and electromagnetic wave tunable technologies, especially to address the difficulty of simultaneously achieving wide-band high optical transparency, adjustable microwave transmission amplitude, and fast response in existing technologies. The invention aims to develop a high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude to achieve the desired performance of wide-band high optical transparency, adjustable microwave transmission amplitude, and fast response.

[0011] The technical solution adopted in this invention is: a high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude, wherein the optical window is composed of an electrically adjustable metasurface layer of integrated patterned phase change material and a transparent dielectric layer arranged in parallel; the electrically adjustable metasurface layer of integrated patterned phase change material is composed of an electrically adjustable metasurface of integrated patterned phase change material, two metal electrodes, and leads connected to the metal electrodes; the electrically adjustable metasurface of integrated patterned phase change material includes a periodically closely arranged m×n electrically adjustable metasurface array units of integrated patterned phase change material, where m≥2, n≥2; the electrically adjustable metasurface array unit of integrated patterned phase change material consists of a metal-gridized double-sided open resonator, a metal-gridized lead A, and a metal-gridized... The device comprises lead-out wire B and a phase change material patch. The metal-gridized double-sided open resonator refers to a device where a through-wire is added to the middle of a metal ring, openings are made on both sides of the through-wire, and the metal portion is replaced by a metal mesh, with the edge portion retaining a metal line width greater than or equal to the metal mesh line width to maintain edge shape characteristics. Metal-gridized lead-out wires A and B refer to two metal lines respectively set at the openings of the metal-gridized double-sided open resonator and led out to the outside of the corresponding openings, neither of which has a metal connection to the metal-gridized double-sided open resonator. The metal portion of metal-gridized lead-out wires A and B is replaced by a metal mesh, and the edge portion retains the line width. Metal lines with a width greater than or equal to the width of the metal mesh grid lines are used to maintain edge shape characteristics; the metal mesh gridded lead-in A and metal mesh gridded lead-in B are respectively connected to the corresponding opening ends of the metal mesh gridded double-sided open resonator through a phase change material patch of at least one; the metal mesh grid refers to a grid-like micro-metal structure composed of grid units arranged in a two-dimensional array; the phase change material patch refers to a tiny patch made of a material that can achieve a reversible change from an insulating phase to a metallic phase under external excitation, and the two-dimensional planar size of a single phase change material patch is on the micrometer scale; the width of the metal electrode A and the metal electrode B is greater than the width of the lead cross-section, and the metal electrode A is connected to the through line of the metal mesh gridded double-sided open resonator, and the metal electrode B is connected to... Metal-gridized lead A and metal-gridized lead B are connected. When the microwave transmission amplitude of the electrically adjustable high-transmittance dual-mode optical window is not energized, the phase change material patch is in the insulating phase. At this time, metal-gridized lead A and metal-gridized lead B are disconnected from the metal-gridized double-sided open resonator. The optical window exhibits a bandpass function in a specific frequency band within the microwave band. When the lead is energized, the phase change material patch begins to transition to the metallic phase, and its sheet resistance gradually decreases. At this time, metal-gridized lead A and metal-gridized lead B will gradually connect with the metal-gridized double-sided open resonator. The optical window exhibits a gradual decrease in the transmission passband amplitude in a specific frequency band within the microwave band until the phase change material patch transitions to the metallic phase, and the microwave transmission passband of the optical window is completely closed.

[0012] As a preferred basic structure, the above-mentioned high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude includes phase change material patches comprising vanadium dioxide, vanadium trioxide, and vanadium oxide.

[0013] As a preferred basic structure, the above-mentioned high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude includes a metal mesh grid, a square mesh grid, a circular mesh grid, a triangular distributed circular ring and sub-circular ring array mesh grid, a metal mesh grid based on randomly distributed circular rings, and a metal mesh grid based on a multi-period nested array of metal circular rings.

[0014] As a preferred basic structure, the above-mentioned high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude includes a phase change material patch connected to the metal-gridized double-sided open resonator and two metal-gridized leads. The connection between the phase change material patch and the metal-gridized double-sided open resonator includes a connection where the phase change material patch is covered by metal and a connection where the metal is covered by the phase change material patch. The thickness of the phase change material is greater than 50 nm.

[0015] As a preferred basic structure, in the above-mentioned high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude, the transparent medium layer can be any transparent material, and the any transparent material can be used as a transparent optical window material that meets the requirements of the application.

[0016] As a preferred basic structure, the above-mentioned high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude has a metal grid-type double-sided opening resonator and two metal grid-type lead-out lines, the width of the metal grid lines of which is on the order of micrometers or submicrometers; the width of the metal electrode is on the order of millimeters; the metal grid-type double-sided opening resonator, the two metal grid-type lead-out lines and the metal electrode are all made of metal with good conductivity, and the metal thickness is greater than 100nm.

[0017] The innovativeness and good effects of this invention are:

[0018] 1. The optical window proposed in this invention is composed of an electrically controllable metasurface layer and a transparent dielectric layer arranged in parallel, with integrated patterned phase change material. The electrically controllable metasurface array unit with integrated patterned phase change material consists of a metal-gridized double-sided open resonator, two metal-gridized leads, and a phase change material patch. The metal-gridized double-sided open resonator and the two metal-gridized leads are not connected by metal. The phase change material patch is used to connect the metal-gridized double-sided open resonator and the two metal-gridized leads. The width of the two metal electrodes is greater than the cross-sectional width of the leads and is respectively connected to the through line of the metal-gridized double-sided open resonator and the two metal-gridized leads. The advantages of this design are that the overall structure of the light window consists of only two layers: a transparent dielectric layer and an electrically adjustable metasurface layer with integrated patterned phase change material, avoiding the design of complex multi-layer structures. The metal-grid double-sided open resonator and two metal-grid leads can be directly used as the feed network for the phase change material patch without the need for an additional complex feed network. In addition, it can be heated to an appropriate temperature when an external voltage is applied, thus enabling rapid de-icing or defogging, avoiding the disadvantage of the long waiting time required for commonly used hot gas de-icing / defogging. When the metal electrodes are not energized, the phase change material patch is in the insulating phase, and the two metal-gridized leads are disconnected from the metal-gridized double-sided open resonator. The optical window functions as a bandpass function within a specific frequency band in the microwave band. When the leads are energized, the phase change material patch begins to transition to the metallic phase, and its sheet resistance gradually decreases. At this time, the two metal-gridized leads and the metal-gridized double-sided open resonator gradually connect, and the optical window's amplitude of the transmission passband within a specific frequency band in the microwave band gradually decreases until the phase change material patch transitions to the metallic phase. The microwave transmission passband of the optical window is then completely closed, and the optical window can achieve strong electromagnetic shielding in a specific frequency band. Therefore, this invention has excellent switching functionality and allows for very convenient continuous adjustment of the microwave transmission amplitude.

[0019] 2. The two-dimensional planar dimensions of the phase change material patch of the present invention are on the micrometer scale, and the external voltage for inducing a single phase change is generally less than 10 volts. Furthermore, since the phase change material patch of the electrically controlled adjustable metasurface array unit integrating patterned phase change material is connected in parallel, the entire structure shares a single bias voltage. Therefore, the control voltage of the present invention is very low. Compared with temperature-induced phase change, the electrical control method of the present invention greatly improves the response speed of optical window electromagnetic control, solving the problems of complex methods and slow response speed of traditional adjustable frequency selection surface control, making it more practical.

[0020] 3. The electrically controllable metasurface layer of the present invention utilizes a metal gridding method, and the micron-scale phase change material patch can ensure that the phase change material has almost no effect on optical transparency. Therefore, its overall structure has high optical transmittance and can achieve high transparency in the visible-infrared broadband band.

[0021] In summary, this invention can simultaneously achieve a wide-band high optical transparency, adjustable microwave transmission amplitude, and fast response time optical window. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic cross-sectional view of a preferred structure of a high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude.

[0024] Figure 2 This is a schematic diagram of the structure of an electrically controllable metasurface layer integrating patterned phase change materials.

[0025] Figure 3 This is a schematic diagram of an electrically controlled tunable metasurface layer array unit integrating patterned phase change materials.

[0026] Figure 4 This is a schematic diagram of different connection methods between phase change material patches and metal.

[0027] Figure 5 This is a schematic diagram of the structure of a metal mesh resonator with two metal mesh leads, and the metal mesh used for the resonator with two metal mesh leads.

[0028] Figure 6 This is a schematic diagram of the structure of Example 1.

[0029] Figure 7 This is a comparison diagram of transmission characteristics under different conditions in Example 1.

[0030] Part numbers in the diagram are explained as follows: 1. Protective layer; 2. Anti-reflective layer; 3. Electrically controlled tunable metasurface layer with integrated patterned phase change material; 4. Transparent dielectric layer; 30. Lead A; 31. Metal electrode A; 32. Lead B; 33. Electrically controlled tunable metasurface array unit with integrated patterned phase change material; 34. Electrically controlled tunable metasurface with integrated patterned phase change material; 35. Metal electrode B; 36. Metal-grid double-sided open resonator; 37. Phase change material patch; 38. Metal-grid lead A; 39. Metal-grid lead B. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments: The object of the present invention is achieved as follows: The optical window is composed of an electrically controllable metasurface layer 3 of integrated patterned phase change material and a transparent dielectric layer 4 arranged in parallel; the electrically controllable metasurface layer 3 of integrated patterned phase change material is composed of an electrically controllable metasurface 34 of integrated patterned phase change material, metal electrode A31, metal electrode B35, lead wire A30, and lead wire B32; the electrically controllable metasurface 34 of integrated patterned phase change material includes m×n electrically controllable metasurface array units 33 of integrated patterned phase change material arranged in close proximity, m≥2, n≥2; the electrically controllable metasurface array units 33 of integrated patterned phase change material... The device comprises a metal-gridized double-sided open resonator 36, metal-gridized leads A38 and B39, and a phase change material patch 37. The metal-gridized double-sided open resonator 36 is constructed by adding a through-line in the middle of a metal ring, opening the metal rings on both sides of the through-line, and finally replacing the metal portion with a metal mesh, while retaining metal lines with a width greater than or equal to the width of the metal mesh lines at the edges to maintain edge shape characteristics. The metal-gridized leads A38 and B39 are two metal lines respectively placed at the openings of the metal-gridized double-sided open resonator 36 and led out to the outside of the corresponding openings, both connected to the metal-gridized double-sided open resonator. The resonator 36 has no metal connection. The metal portions of the metal-gridized leads A38 and B39 are replaced by metal meshes, and the edge portions retain metal lines with a line width greater than or equal to the width of the metal mesh lines to maintain edge shape characteristics. The metal-gridized leads A38 and B39 are respectively connected to the corresponding opening ends of the metal-gridized double-sided open resonator 36 through at least one phase change material patch 37. The metal mesh refers to a grid-like micro-metal structure composed of mesh units arranged in a two-dimensional array. The phase change material patch 37 refers to a tiny patch made of a material that can reversibly change from an insulating phase to a metallic phase under external excitation. The two-dimensional planar dimensions of the phase change material patch 37 are on the micrometer scale; the widths of the metal electrodes A31 and B35 are greater than the width of the cross-section of the lead 32, and the metal electrode A31 is connected to the through-line and lead B32 of the metal-gridized double-sided open resonator 36, respectively; the metal electrode B35 is connected to the metal-gridized lead A38, metal-gridized lead B39, and lead A30, respectively; when the microwave transmission amplitude can be electrically controlled and adjusted, the phase change material patch 37 is an insulating phase, and at this time the metal-gridized lead A38 and metal-gridized lead B39 are disconnected from the metal-gridized double-sided open resonator 36; the optical window exhibits a bandpass function in a specific frequency band within the microwave band.When leads A30 and B32 are energized, the phase change material patch 37 begins to transition to the metallic phase, and its sheet resistance gradually decreases. At this time, the metal-gated leads A38 and B39 gradually connect with the metal-gated double-sided open resonator 36. The optical window exhibits a gradual decrease in the amplitude of the transmission passband within a specific frequency band in the microwave band until the phase change material patch 37 transitions to the metallic phase, and the microwave transmission passband of the optical window is completely closed.

[0032] Figure 1 This is a schematic cross-sectional view of a preferred structure for a high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude. The transparent dielectric layer 4 can be any transparent material, as long as it can serve as a transparent optical window material that meets the requirements of the application. At the same time, the electrically adjustable metasurface layer 3 with integrated patterned phase change material can be processed onto the surface of the transparent dielectric layer 4 according to a certain process. A single or multiple antireflective film 2 enhances the light transmittance of the optical window. A single or multiple protective layer 1 is used to protect the electrically adjustable metasurface layer 3 with integrated patterned phase change material to prevent the metal and phase change material patch 37 from being scratched or corroded and oxidized due to long-term exposure to air, thus avoiding affecting the overall performance of the optical window. In practical applications, the transparent dielectric layer 4 and the electrically adjustable metasurface layer 3 with integrated patterned phase change material are indispensable factors of this invention. Depending on the process and actual application scenario, the antireflective film 2 and the protective layer 1 may or may not be present.

[0033] Figure 2 This is a schematic diagram of the structure of an electrically controllable metasurface layer with integrated patterned phase change materials. As shown in the figure, the electrically controllable metasurface layer 3 with integrated patterned phase change materials consists of an electrically controllable metasurface 34 with integrated patterned phase change materials, metal electrode A31, metal electrode B35, lead wire A30, and lead wire B32. The electrically controllable metasurface 34 with integrated patterned phase change materials includes a periodically closely arranged array of m×n electrically controllable metasurface units 33 with integrated patterned phase change materials, where m≥2 and n≥2. The metal electrodes 31A and B35, as well as leads A30 and B32 shown in the figure, are for illustrative purposes only. The width of the two metal electrodes is greater than the cross-section and width of the leads. Metal electrode A31 is connected to the through-line of the metal-grid double-sided open resonator 36, and metal electrode B35 is connected to the metal-grid leads A38 and B39. An external power supply is responsible for providing voltage to the leads. Different driving voltages can be selected according to the different tuning sheet resistances of the phase change material patch 37.

[0034] Figure 3This is a schematic diagram of the structure of the electrically controlled tunable metasurface array unit integrating patterned phase change material in this invention. The electrically controlled tunable metasurface array unit 33 integrating patterned phase change material consists of a metal-gridized double-sided open resonator 36, a metal-gridized lead A38, a metal-gridized lead B39, and a phase change material patch 37; the two metal-gridized leads are respectively connected to the corresponding open ends of the metal-gridized double-sided open resonator through at least one phase change material patch.

[0035] Figure 4 The diagrams show different connection methods between the phase change material patch 37 and the metal-gridized leads A38, B39, and the metal-gridized double-sided open resonator 36. (a) shows a connection where the phase change material is covered by metal. This requires first processing the phase change material patch 37 using a combination of phase change material growth and photolithography etching, followed by processing the metal using a combination of ultraviolet lithography and metal growth. (b) shows a connection where the metal is covered by phase change material. This method requires first processing the metal using a combination of ultraviolet lithography and metal growth, followed by processing the phase change material patch 37 using a combination of phase change material growth and photolithography etching.

[0036] Figure 5 Schematic diagrams of different types of metal mesh structures are shown: (a) a square mesh, (b) a ring mesh, (c) a triangularly distributed ring and sub-ring array mesh, (d) a metal mesh based on randomly distributed rings, and (e) a nested array mesh based on multi-period metal rings. (a) and (b) show the basic structures of metal meshes. Based on these, many other types of metal meshes exist, such as (c) with introduced sub-ring structures, (d) with added random elements, and (e) utilizing multiple periods. These three types of metal meshes can further improve the uniformity of the high-order diffraction energy distribution in the electrically controlled tunable metasurface layer of integrated patterned phase change materials, solving the problem of poor imaging quality caused by the concentrated high-order diffraction energy distribution on the frequency-selective surface of traditional metal meshes. In applications requiring high imaging quality, these types of meshes can be used to reduce the impact on the imaging system.

[0037] To facilitate understanding of the present invention, the invention will be described more clearly and completely below in conjunction with the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0038] Example 1:

[0039] According to one embodiment of the invention, for example Figure 6 As shown in the diagram, its overall structure is as follows: Figure 6 As shown in (a), it consists of an electrically controllable tunable metasurface layer with patterned phase change material integrated on top and a transparent dielectric layer. A schematic diagram of the electrically controllable tunable metasurface layer with patterned phase change material integrated is shown below. Figure 6As shown in (b). In this example, the metal mesh used for the electrically controllable metasurface layer integrating patterned phase change material is a square metal mesh; the transparent dielectric layer is made of sapphire with a dielectric constant of ε1 = 9.4; the phase change material patch is made of electrically controllable vanadium dioxide, which is an insulating phase with a sheet resistance greater than 100,000 Ω when the external voltage is less than the phase change voltage, and a metallic phase with a sheet resistance less than 80 Ω when the external voltage is greater than the phase change voltage. When the external voltage reaches the phase change voltage, vanadium dioxide can transform from an insulating phase to a metallic phase in a sub-picosecond timescale; the thickness of the vanadium dioxide patch is 200 nm, and the thickness of the metal is 300 nm; the metal and vanadium dioxide patches are made of... Figure 4 The connection is made in the manner described in (a); the metal used is copper. The voltage drive of the vanadium dioxide patch is achieved by an external voltage directly supplying power to an electrically controlled, adjustable metasurface with an integrated patterned phase change material via leads and metal electrodes. This power is supplied directly to the patch via a metal gridded double-sided open resonator and two metal gridded leads, thereby controlling the phase change of the vanadium dioxide patch. Compared to other reported optical windows that utilize temperature to control phase change, the high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude of this invention has a controllable response time that is only affected by the voltage signal and the sub-picosecond electrically controlled phase change time of the vanadium dioxide patch itself, without needing to wait for the heating process of the vanadium dioxide patch. Therefore, the optical window of this invention has an extremely fast controllable response speed and can adapt to applications requiring rapid response.

[0040] Since transmittance is one of the key parameters of the electrically adjustable microwave transmission amplitude high-transmittance dual-mode optical window, the transmittance of the sample in Example 1 was analyzed. The transmittance of the grid grating used in the electrically adjustable frequency selective surface layer of the integrated patterned phase change material is 90%. Although the transmittance of the phase change material in the metallic phase is poor (only 30%), the total area of ​​the vanadium dioxide patches used is only 0.02%, so the influence of the vanadium dioxide patches on the transmittance is negligible. The transmittance of the entire electrically adjustable frequency selective surface layer of the integrated phase change material is 96.5%. In summary, the electrically adjustable microwave transmission amplitude optical window designed in this invention has extremely high transmittance and can be adapted to applications requiring high transparency.

[0041] The effects of this invention can be achieved through Figure 7 Further explanation:

[0042] Simulations of the transmission characteristics of this embodiment were performed using different voltage values, and the results are as follows: Figure 7As shown in the figure, when no power is applied (V1 = 0V), the vanadium dioxide patch is in the insulating phase. At this time, the optical window generates a transmission passband with a resonant frequency of 10.861GHz and a passband loss of 1.08dB. As the external voltage increases, the amplitude of the transmission passband of the optical window gradually decreases until the vanadium dioxide patch phase changes to the metallic phase, and the microwave transmission passband of the optical window is completely closed. At this time, the transmission amplitude at the original transmission passband of 10.861GHz is only -12.7dB, and it can provide electromagnetic shielding of more than 11dB in the range of 2 to 12GHz. Therefore, the present invention has a large microwave transmission amplitude tuning range, low passband loss, and can provide strong electromagnetic shielding in the off state.

[0043] The above description is only one specific example of the present invention. Obviously, those skilled in the art, after understanding the content and principle of the present invention, may make various modifications and changes in form and detail without departing from the principle and structure of the present invention. However, these modifications and changes based on the idea of ​​the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude, characterized in that: The optical window is composed of an electrically controllable metasurface layer (3) of integrated patterned phase change material and a transparent dielectric layer (4) arranged in parallel. The electrically controllable metasurface layer (3) of integrated patterned phase change material is composed of an electrically controllable metasurface (34) of integrated patterned phase change material, metal electrode A (31), metal electrode B (35), lead A (30) and lead B (32). The electrically controllable metasurface (34) of integrated patterned phase change material includes m×n electrically controllable metasurface array units (33) of integrated patterned phase change material arranged in close proximity, m≥2, n≥2. The electrically controllable metasurface array unit (33) of integrated patterned phase change material is composed of a metal gridded double-sided open resonator (36) and a metal grid. The device consists of a metal mesh lead-out line A (38), a metal mesh lead-out line B (39), and a phase change material patch (37). The metal mesh double-sided open resonator (36) refers to a device in which a through-line is added in the middle of a metal ring, the metal rings on both sides of the through-line are opened, and the metal part is replaced by a metal mesh. The edge part retains a metal line with a line width greater than or equal to the line width of the metal mesh to maintain the edge shape characteristics. The metal mesh lead-out line A (38) and the metal mesh lead-out line B (39) refer to two metal lines respectively set at the opening of the metal mesh double-sided open resonator (36) and led out to the outside of the corresponding opening. Neither of them has a metal connection with the metal mesh double-sided open resonator (36). The metal portions of the meshed lead-in A (38) and the metal meshed lead-in B (39) are replaced by metal meshes, and the edge portions retain metal lines with a line width greater than or equal to the line width of the metal mesh to maintain the edge shape characteristics; the metal meshed lead-in A (38) and the metal meshed lead-in B (39) are respectively connected to the corresponding opening ends of the metal meshed double-sided open resonator (36) through a phase change material patch (37) of at least one; the metal mesh refers to a mesh-like micro-metal structure composed of mesh units arranged in a two-dimensional array; the phase change material patch (37) refers to a tiny patch made of a material that can achieve a reversible change from an insulating phase to a metallic phase under external excitation, and a single phase change material patch (37) The two-dimensional plane size is on the micrometer level; the width of the metal electrode A (31) and metal electrode B (35) is greater than the width of the cross-section of the lead wire A (30) and B (32), and the metal electrode A (31) is connected to the through line and lead wire B (32) of the metal gridded double-sided open resonator (36) respectively, and the metal electrode B (35) is connected to the metal gridded lead wire A (38), metal gridded lead wire B (39) and lead wire A (30) respectively; when the microwave transmission amplitude can be electrically controlled and adjusted, the phase change material patch (37) is an insulating phase, and at this time the metal gridded lead wire A (38) and metal gridded lead wire B (39) are disconnected from the metal gridded double-sided open resonator (36) and have no connection;The optical window functions as a bandpass function within a specific frequency band in the microwave band. When leads A (30) and B (32) are energized, the phase change material patch (37) begins to transition to the metallic phase, and its sheet resistance gradually decreases. At this time, the metal-gated leads A (38) and B (39) gradually connect with the metal-gated double-sided open resonator (36), and the optical window functions as a bandpass amplitude that gradually decreases within a specific frequency band in the microwave band until the phase change material patch (37) transitions to the metallic phase, and the microwave transmission passband of the optical window is completely closed.

2. The high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude according to claim 1, characterized in that: The phase change material patch (37) includes vanadium dioxide, vanadium trioxide, and vanadium oxide.

3. The high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude according to claim 1, characterized in that: The metal mesh includes square mesh, circular mesh, triangular distributed circular and sub-circular array mesh, metal mesh based on randomly distributed circular rings, and metal mesh based on multi-period nested array of metal circular rings.

4. The high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude according to claim 1, characterized in that: The connection methods of the phase change material patch (37) with the metal gridded lead A (38), the metal gridded lead B (39), and the metal gridded double-sided open resonator (36) include the connection where the phase change material is covered by metal and the connection where the metal is covered by phase change material. The thickness of the patterned phase change material is greater than 50 nm.

5. The high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude according to claim 1, characterized in that: The transparent medium layer (4) can be any transparent material, which can be used as a transparent light window material that meets the requirements of the application.

6. The high-transmittance dual-mode optical window with electrically adjustable microwave transmission amplitude according to claim 1, characterized in that: The width of the metal grid lines in the metal grid of the metal-grid double-sided open resonator (36), metal-grid lead A (38) and metal-grid lead B (39) is on the order of micrometers or submicrometers; the width of the metal electrode A (31) and metal electrode B (35) is on the order of millimeters; the metal-grid double-sided open resonator (36), metal-grid lead A (38), metal-grid lead B and metal electrode A (31) and metal electrode B (35) are all made of metal with good conductivity and the metal thickness is greater than 100 nm.

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