Reconfigurable metasurface device with broadband and polarization independent characteristic

Abstract

The invention discloses a reconfigurable metasurface device with broadband and polarization independent characteristics, and belongs to the technical field of microwaves. And dynamic regulation and control of linearly polarized and circularly polarized waves can be realized in a wide frequency band. Comprising a visual closed-loop control system, a rotating motor array and a substrate unit array, the visual closed-loop control system comprises an image acquisition module, a unit angle identification module and a unit angle control module; the image acquisition module is used for shooting a metasurface image; the unit angle identification module is used for identifying the type and the rotating direction angle of each substrate unit; the unit angle control module is used for controlling each substrate unit to rotate so as to realize a layout structure of a target; the device has the characteristics of wide frequency band, polarization independence and quick response. The method has wide application prospects in the fields of radar systems, satellite communication, imaging, sensing and the like, can meet the requirements of modern communication and imaging technologies for high performance and dynamic response, and has remarkable market value and industrialization potential.

Description

Technical Field

[0001] The present invention belongs to the field of microwave technology, and in particular relates to a reconfigurable metasurface device with broadband and polarization-independent characteristics. Background Art

[0002] Metasurfaces are two-dimensional structures composed of periodic or quasi-periodic arrangements of artificial units at the subwavelength scale. They can flexibly control parameters such as the amplitude, phase, and polarization of electromagnetic waves. Traditional metasurfaces are typically fixed structures, and once fabricated, their electromagnetic properties are difficult to modify, limiting their potential for dynamic control and multifunctional applications. To address this, reconfigurable metasurfaces have emerged. By introducing controllable units and actuation mechanisms, metasurfaces are endowed with real-time reconfiguration capabilities, enabling flexible control of electromagnetic responses based on external commands.

[0003] The fusion of broadband characteristics and polarization independence is a huge difficulty in the design of reconfigurable metasurfaces. Most reconfigurable metasurface designs can only work under the excitation of one of the feed sources, linearly polarized waves or circularly polarized waves. Therefore, broadband characteristics and polarization independence are important requirements for the design of reconfigurable metasurfaces. Broadband response means that the device can operate stably in a wide frequency range and adapt to complex electromagnetic environments; polarization independence enables it to maintain consistent control effects under different incident polarization states, greatly improving the robustness of the system and the breadth of application scenarios, and removing the restrictions of the metasurface on the polarization state of the incident antenna. To achieve reconfigurable metasurfaces with broadband and polarization independence characteristics, it is usually necessary to coordinate optimization through special unit structure design, material selection, and dynamic control methods.

[0004] Reconfigurable metasurfaces are subject to manufacturing errors during the manufacturing process, such as poor motor consistency; varying friction on the motor shaft due to assembly errors; and power supply voltage fluctuations during operation. These factors can lead to errors in the adjustment of the metasurface during operation. Therefore, a closed-loop vision system is introduced to monitor the real-time changes in the angle of the metasurface's substrate units through visual feedback, stopping the motor drive when the preset angle is reached. Summary of the Invention

[0005] The purpose of the present invention is to provide a reconfigurable metasurface device with broadband and polarization-independent characteristics to address the problems of traditional metasurfaces having fixed functions after preparation, the difficulty of existing reconfigurable metasurfaces to simultaneously achieve broadband response and polarization-independence, and the difficulty of substrate units to achieve multi-order phase control. The device can achieve dynamic adjustment through the combination of a rotating motor and a substrate unit, improve the phase order based on a visual closed-loop control system, and stably control arbitrarily polarized electromagnetic waves within a wide bandwidth.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions.

[0007] A reconfigurable metasurface device with broadband and polarization-independent properties, comprising a rotation motor array, a substrate unit array, and a visual feedback control system;

[0008] Each substrate unit in the substrate unit array comprises a dielectric substrate, the lower surface of each dielectric substrate is completely covered by a metal plane, and a metal pattern is etched on the upper surface of the dielectric substrate; the metal pattern has the structural characteristics of an anisotropic patch, and the metal pattern structure itself has the characteristics of a geometric phase unit;

[0009] Each rotor of the rotating motor array is fixedly connected to a substrate unit, which is combined with the rotating motor to form a rotatable unit; the rotatable unit is used to dynamically control the reflection amplitude and reflection phase of arbitrarily polarized electromagnetic waves; the reconfigurable metasurface is composed of hundreds of rotatable units, which are arranged in a periodic array structure to construct a complete metasurface system and achieve coordinated control of electromagnetic waves;

[0010] The visual feedback control system includes an image acquisition module, a unit angle recognition module and a unit angle control module; the image acquisition module is used to capture the metasurface image; the unit angle recognition module is used to identify the type and rotation angle of each substrate unit; and the unit angle control module is used to control the rotation of each substrate unit to achieve the target layout structure.

[0011] Furthermore, the substrate unit is a reflective metasurface unit, which is composed of a metal base plate and a metal pattern covered on a dielectric substrate, and the substrate units are arranged in a periodic arrangement.

[0012] Furthermore, the substrate unit is designed as a geometric phase type unit to satisfy the total reflection of the incident waves polarized along the x-axis and y-axis, and the reflection phase difference in the orthogonal direction is 180°.

[0013] Furthermore, the substrate unit achieves stable control of the reflection amplitude for both linearly polarized waves and circularly polarized waves within the operating frequency band of 10 to 14 GHz, wherein the reflection amplitude under circularly polarized wave excitation exceeds 0.9.

[0014] Furthermore, the substrate unit array is composed of units with different metal patterns arranged alternately in a checkerboard pattern. Each substrate unit can rotate freely 360° along with the rotor of the rotating motor. The amplitude and phase of the incident wave with different polarization states are modulated by controlling the rotation angle to achieve different phase encoding.

[0015] Furthermore, the metal pattern consists of a cross-shaped patch and four arc-shaped patches.

[0016] Furthermore, the metal pattern has obvious anisotropy characteristics. The metal pattern is used to realize the electromagnetic control characteristics of the geometric phase unit. Combined with the free rotation operation, it can achieve the combination of broadband and polarization-independent characteristics.

[0017] Furthermore, the upper surface metal pattern and the lower surface metal plane are both made of copper material.

[0018] Furthermore, the reconfigurable metasurface is an array structure composed of units with different metal patterns, which is used to achieve different phase coding arrangements.

[0019] Furthermore, the reconfigurable metasurface is used to achieve independent control of the rotation angle of the substrate unit, and the angles between two adjacent substrate units will not be coupled with each other.

[0020] Furthermore, the reconfigurable metasurface is a reflective electromagnetic device, which utilizes a metal plane that fully covers the lower surface of the unit substrate to achieve total reflection of the incident electromagnetic wave.

[0021] Furthermore, the dielectric substrate can be made of high-performance high-frequency dielectric material with a relative dielectric constant of =3.0.

[0022] Furthermore, the array image acquisition module includes a metasurface array structure and a camera, which is used to obtain images of all units in the metasurface; the unit angle recognition module includes a computing board and a neural network algorithm, which is used to identify the rotation angle of each unit; the unit angle control module includes a motor control circuit and a motor control algorithm, which is used to drive the motor device to drive the unit substrate to reach the target rotation angle.

[0023] Furthermore, the camera in the array image acquisition module is connected to the computing board in the unit angle recognition module; and the computing board in the unit angle recognition module is connected to the motor control circuit in the unit angle control module.

[0024] Furthermore, the unit angle recognition module includes a computing board and a neural network algorithm; the computing board is connected to the motor control circuit and is used to process multiple input substrate unit images in parallel; the neural network algorithm is used to simultaneously identify the metal pattern type and rotation angle of the substrate unit.

[0025] Furthermore, by incorporating neural network unit recognition into the visual closed-loop control system, parallel GPU monitoring can be achieved. The number of baseboard units can often reach hundreds or even thousands, and the neural network algorithm can adapt to the parallel processing architecture of the GPU to calculate the angles of all units in parallel, ensuring real-time operation efficiency of the device.

[0026] Furthermore, the visual closed-loop control system includes:

[0027] Array image acquisition module: contains the metasurface array structure and a camera, used to collect images of all units in the metasurface;

[0028] The unit angle recognition module includes a computing board and a neural network algorithm. The computing board is connected to the motor control circuit in the unit angle control module and is used to process multiple input substrate unit images in parallel. The neural network algorithm is used to simultaneously identify the metal pattern type and rotation angle of the substrate unit.

[0029] Unit angle control module: Contains motor control circuit and motor control algorithm, used to drive the motor to adjust the unit substrate to the final rotation angle according to the angle difference.

[0030] Furthermore, the camera is electrically connected to the computing board, and the computing board is electrically connected to the motor control circuit, forming a closed-loop link of image acquisition-recognition-control.

[0031] Furthermore, the computing board supports parallel processing of multi-unit images, and the neural network algorithm can simultaneously identify the metal pattern type and real-time rotation angle of the unit, adapting to the GPU parallel computing architecture.

[0032] Furthermore, the visual closed-loop control system uses visual image processing to complete the closed-loop operation of the entire control; the image acquisition module obtains the image of each substrate unit on the metasurface, and the unit angle recognition module recognizes the angle of the substrate unit and compares the difference between the preset angle and the recognized angle; based on the angle difference, the unit angle control module is used to complete the motor rotation control, and the motor rotation is stopped after reaching the target angle.

[0033] This paper proposes a reconfigurable metasurface device and control scheme based on visual feedback. By utilizing camera image acquisition, AI (Artificial Intelligence) to identify unit states, and real-time motor drive adjustments, the system significantly improves reconstruction speed and accuracy. This system, capable of achieving sub-second response times, meets the urgent need for highly flexible electromagnetic control in applications such as radar systems, satellite communications, dynamic imaging, and intelligent sensing, demonstrating broad application prospects and significant engineering value.

[0034] Combining the unique characteristics of a rotating motor and a dielectric substrate unit, this invention innovatively proposes a reconfigurable metasurface device with broadband and polarization-independent properties. This structure demonstrates the ability to dynamically control electromagnetic waves of arbitrary polarization over a wide frequency band. The two designed substrate units enable the free manipulation of arbitrary linearly and circularly polarized waves, thus achieving polarization-independence.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The present invention realizes a reconfigurable metasurface device by combining a rotating motor and a substrate unit. Compared with the existing design methods, the design scheme of the present invention can realize real-time monitoring of the structure of the metasurface device. In addition, the reconfigurable metasurface device can combine the three superior characteristics of broadband response, polarization independence and dynamic adjustability, and can be applied to the wavefront control of electromagnetic waves. Other metasurface devices cannot integrate the above three superior characteristics into the same electromagnetic device. The reconfigurable metasurface device can be applied to radar systems, satellite communications, imaging and sensing and other fields, and has broad application prospects. In addition, due to the dynamic adjustable characteristics of the device of the present invention, the integration of the metasurface array can be greatly improved, and it can be applied to the control of multiple different electromagnetic wavefronts. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the overall reconfigurable metasurface device according to an embodiment of the present invention.

[0038] Figure 2 Schematic diagram of the size structure of a single circular dielectric substrate and a metal pattern according to an embodiment of the present invention.

[0039] Figure 3 1 and 2 are simulation results of the reflection amplitude of linearly polarized waves for two substrate units according to an embodiment of the present invention.

[0040] Figure 4 1 and 2 are simulation results of the reflection phase of linearly polarized waves for two substrate units according to an embodiment of the present invention.

[0041] Figure 5 These are simulation results of the circularly polarized wave reflection amplitudes of the two substrate units according to an embodiment of the present invention.

[0042] Figure 6 1 and 2 are simulation results of the reflection phase of circularly polarized waves of two substrate units according to an embodiment of the present invention.

[0043] Figure 7 The figure shows the simulation results of the reconfigurable metasurface according to an embodiment of the present invention applied to linear polarization holographic imaging.

[0044] Figure 8 The figure shows the simulation results of the reconfigurable metasurface according to an embodiment of the present invention applied to circularly polarized holographic imaging.

[0045] Figure 9 The image acquisition module of the embodiment of the present invention completes the acquisition, correction and segmentation of the hypersurface image.

[0046] Figure 10 This is the process of the unit angle recognition module in an embodiment of the present invention from acquiring an image to outputting the unit type and angle.

[0047] Figure 11This is the prediction result of the unit type and angle of the substrate unit image by the unit angle recognition module of an embodiment of the present invention.

[0048] Figure 12 Schematic diagram of the connection between the control circuit and the motor in the angle control module according to an embodiment of the present invention.

[0049] Figure 13 This is a layout diagram of the connection between the control circuit and the motor in the angle control module of an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the purpose, technical solutions and beneficial effects of the present invention, the following will be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the examples listed are only used to explain the present invention, rather than to limit the technical solutions of the present invention.

[0051] The embodiment of the present invention provides a reconfigurable metasurface device with broadband and polarization-independent characteristics, such as Figure 1 As shown, the reconfigurable metasurface device 100 includes a visual closed-loop control system 101, a rotating motor array 102, and a substrate unit array 103. The rotating motor array 102 is composed of multiple independent rotating motors, each of which has a substrate unit of the substrate unit array 103 fixedly connected to its rotor. These substrate units rotate along with the rotor of the rotating motor array 102 to achieve 360° free rotation. These rotating motors and substrate units are combined to form rotatable units, and all rotatable units can be controlled by the visual closed-loop control system 101 set outside the rotating motor array 102. It should be noted that the substrate unit array 103 of the reconfigurable metasurface device is arranged alternately in a checkerboard pattern using two types of units (e.g., a first substrate unit 201 and a second substrate unit 202).

[0052] The workflow of the visual closed-loop control system 101 may include: a camera acquires an image of each substrate unit on the metasurface; a neural network algorithm of a unit angle recognition module recognizes the angle of the substrate unit and compares the difference between a preset angle and the recognized angle; based on the angle difference, a unit angle control module is used to complete motor rotation control, and the motor rotation is stopped after the target angle is reached.

[0053] like Figure 2 As shown, the substrate unit 200 of this embodiment is a design template for a reflective metasurface unit. The upper surface is a metal pattern composed of a cross-shaped patch and four arc-shaped patches, the lower surface is a fully covered metal plane, and the dielectric substrate in the middle is F4B high-frequency dielectric material with a relative dielectric constant of =3.0, the dielectric substrate radius r = 6.0 mm, and the dielectric substrate thickness h = 3.0 mm. Using substrate unit 200 as a design example, structural parameters on the patch were modified and iterative simulations were performed to determine two substrate units (i.e., first substrate unit 201 and second substrate unit 202). These two substrate units are controlled by a control system connected to a rotary motor to achieve rotational operation, which is used to achieve amplitude and phase control of incident waves with different polarization states.

[0054] Figure 2 In the figure, 200 is a design example of a substrate unit, and the first substrate unit 201 and the second substrate unit 202 are two better units obtained by modifying and optimizing structural parameters based on the substrate unit example 200, which are used to realize amplitude and phase control of electromagnetic waves.

[0055] For example, the first and second substrate units 201 and 202 are designed according to the characteristics of a geometric phase unit, ensuring that the substrate units can achieve total reflection for incident waves polarized along the x- and y-axes, and that the reflection phase difference in the orthogonal directions is 180°. The metal pattern exhibits significant anisotropy, enabling the electromagnetic control characteristics of a geometric phase unit. Combined with free rotation operation, this allows for a combination of broadband and polarization-independent characteristics.

[0056] Exemplarily, the upper surface metal pattern and the lower surface metal plane of the substrate unit are both made of full copper material.

[0057] For example, two substrate units with different upper surface metal patterns are designed: the structural parameters of the first substrate unit 201 are as follows: arc angle 1 =83.0°, arc angle 2 =0.0°, the length of the longer branch of the cross patch =6.0 mm, the shorter branches of the cross patch =0.0 mm, the width of all curved patches =1.4 mm, the width of the longer branch of the cross patch =1.5 mm, the width of the shorter branch of the cross patch =0.0 mm. The structural parameters corresponding to the second substrate unit 202 are as follows: arc angle 1 =43.0°, arc angle 2 =59.9°, the length of the longer branch of the cross patch =7.0 mm, the shorter branches of the cross patch =5.4 mm, the width of all curved patches =1.4 mm, the width of the longer branch of the cross patch =0.6 mm, the width of the shorter branch of the cross patch =1.5 mm.

[0058] It should be noted that the two substrate units in the above embodiments are only examples, and the structural parameters of the corresponding units are not unique. By iteratively optimizing their structural parameters, the designed substrate units can be applied to millimeter wave, terahertz or optical frequency bands.

[0059] like Figure 3 As shown in the figure, the reflection amplitudes of the two substrate unit structures of this embodiment are simulated under linear polarization wave excitation, where α represents the rotation angle of the substrate unit. Within the entire operating frequency band (10~14 GHz), the reflection amplitude of the unit remains basically stable. The specific values ​​of the rotation angle of the substrate unit are 0.6 ( °), 0.8 ( °) and 1.0 ( °). The left picture shows the first substrate unit, and the right picture shows the second substrate unit.

[0060] like Figure 4 As shown in the figure, the reflection phases of the two substrate unit structures of this embodiment are simulated under linear polarization wave excitation, where α represents the rotation angle of the substrate unit. The reflection phase can be switched between 0° and 180° in a second-order manner corresponding to clockwise and counterclockwise rotation of the substrate unit. Figure 4 In the figure, the left picture shows the first substrate unit, and the right picture shows the second substrate unit.

[0061] like Figure 5 As shown in the figure, the reflection amplitudes of the two substrate unit structures of this embodiment were simulated under circularly polarized wave excitation, where α represents the rotation angle of the substrate unit. The reflection amplitude of the unit remains basically stable across the entire operating frequency band (10-14 GHz). The reflection amplitudes of the substrate units at different rotation angles all exceed 0.9, indicating that total electromagnetic wave reflection is achieved. The left figure shows the first substrate unit, and the right figure shows the second substrate unit.

[0062] like Figure 6 As shown in the figure, the reflection phases of the two substrate unit structures of this embodiment are simulated under circularly polarized wave excitation, where α represents the rotation angle of the substrate unit. By controlling the rotation angle of the substrate unit, the reflection phase can be continuously and freely adjusted. When the first substrate unit 201 and the second substrate unit 202 are rotated counterclockwise by 45°, their reflection phase decreases by 90°. The left figure shows the first substrate unit, and the right figure shows the second substrate unit.

[0063] For example, to verify the imaging characteristics of the reconfigurable metasurface device of this embodiment, three typical frequencies within the working frequency band are selected: 10 GHz, 12 GHz, and 14 GHz. The imaging height of the holographic image is set to 450 mm, and the imaging area is set to 500×500 mm. 2 .

[0064] like Figure 7 As shown, the reconfigurable metasurface device of this embodiment can achieve holographic imaging and obtain multiple different field intensity images under the excitation of linear polarization waves. The corresponding amplitude map and phase map are calculated based on the target image to determine the structural distribution of each substrate unit on the metasurface. The theoretical and simulated field intensity images are calculated based on the Rayleigh-Sommerfeld diffraction model and electromagnetic software, and the theoretical image and the simulated image are highly consistent. Figure 7 The three small figures a, b, and c show the application of the reconfigurable metasurface in character XYZ image generation. Figure 7 The three small figures d, e, and f show the application of the reconfigurable metasurface in multi-focus point image generation, which demonstrates that the device can switch between multiple field strength images within the working frequency band.

[0065] like Figure 8 As shown in the figure, the reconfigurable metasurface device of this embodiment can realize holographic imaging and obtain multiple different field intensity images under the excitation of circularly polarized waves. The structural distribution of each substrate unit on the metasurface is determined by calculating the corresponding phase map based on the target image. There is a high degree of consistency between the theoretical calculation and the software simulation field intensity images. Figure 8 In the six small figures a, b, c and d, e, and f, XYZ character images and multi-focus point images can be obtained, which also verifies that the reconfigurable metasurface can generate images with different field strengths, demonstrating the high integration and high degree of freedom characteristics of the reconfigurable metasurface device under circularly polarized wave excitation.

[0066] The control system of each rotatable unit in the reconfigurable metasurface device of this embodiment is as follows: Figure 9 As shown, it includes a metasurface image acquisition module, a unit angle recognition module and a unit angle control module.

[0067] The image acquisition module of this embodiment includes a camera and an image calibration algorithm to complete the image acquisition, correction and cutting operations, such as Figure 9 As shown in the figure, the metasurface image captured by the camera exhibits barrel distortion, meaning the center of the image bulges outward. Therefore, an image calibration algorithm is used to geometrically correct the distorted metasurface image. To facilitate subsequent angular identification of the substrate units, the entire metasurface array is divided into a 16×16 uniform grid along 17 horizontal and 17 vertical lines, resulting in 256 independent substrate unit images.

[0068] The unit angle recognition module of this embodiment includes an AI computing board and a neural network model. The following is an example of the process from image input to unit angle output. Figure 10 As shown. After the image acquisition module obtains 256 corrected substrate unit images, the AI ​​computing board is used to receive the obtained substrate unit images. The image processing is completed in parallel through the designed neural network model, and the type and angle corresponding to each unit image are output. Figure 11 As shown, the designed neural network model can accurately identify the type and angle of the substrate unit.

[0069] The unit angle control module of this embodiment includes a control circuit and a motor control algorithm. The following is an example of connecting a 16×16 rotating motor array with the control circuit. Figure 12 As shown in the figure, for example, the positive terminal of each motor is connected to a high level, while the negative terminal is connected to a control circuit. The control circuit then outputs a low-level signal to each negative terminal to rotate the motor rotor. The motor control algorithm calculates the difference between the current base unit angle and the target angle, converting it into a corresponding pulse signal time, which is used to control the rotation time of the motor rotor and achieve angle adjustment.

[0070] In this embodiment, 256 motors need to be individually controlled, so they are divided into 4 identical circuit modules to further simplify the circuit complexity. Each module contains a single-chip microcomputer and 8 ULN2803 motor driver chips to achieve the control of 64 motors. Each single-chip microcomputer uses a serial port to obtain the pulse data of the 64 rotatable units calculated by the computing board. Figure 13 The design layout of the circuit module is shown in the figure. The large yellow square area in the center is the location of the microcontroller, while the two rows of rectangular yellow boxes in the middle are the locations of the eight ULN2803 chips. The 64 gray areas on the outermost edge are used to connect to the wiring ports of the 64 motors.

[0071] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention. The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of protection required.

Claims

1. A reconfigurable metasurface device with broadband and polarization-independent properties, characterized in that It includes a substrate unit array, a rotary motor array and a visual closed-loop control system; Each substrate unit in the substrate unit array comprises a dielectric substrate, the lower surface of the dielectric substrate is covered with a metal plane, and the upper surface is etched with an anisotropic metal pattern, and the metal pattern has the electromagnetic control characteristics of the geometric phase unit to achieve the control of electromagnetic waves with different polarization states; The motor rotor of the rotating motor array is fixedly connected to the base plate unit, driving the base plate unit to achieve 360° free rotation, and the angle control of adjacent units is not coupled with each other; The visual closed-loop control system is used to monitor and calibrate the rotation angle of the substrate unit in real time.

2. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 1, characterized in that The substrate unit is a reflective unit, which consists of a metal bottom plate, a dielectric substrate and a metal pattern on the upper surface, which are arranged in a periodic array and use the metal plane on the lower surface to achieve total reflection of the incident electromagnetic wave.

3. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 2, characterized in that The metal pattern on the upper surface is a combination of a cross-shaped patch and four arc-shaped patches, which has obvious anisotropy. Combined with the rotation operation, dynamic control of the phase and amplitude of arbitrarily polarized electromagnetic waves within a broadband range can be achieved.

4. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 1, characterized in that The substrate unit array is composed of at least two units with different metal patterns, which are alternately arranged in a chessboard pattern, so as to realize different phase encoding.

5. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 1, characterized in that The substrate unit is designed as a geometric phase-type unit, achieving total reflection of incident waves polarized along the x-axis and y-axis, with a reflection phase difference of 180° in the orthogonal direction. The reflection amplitudes of both linearly polarized waves and circularly polarized waves are stable and controllable within the 10-14 GHz frequency band, with the reflection amplitude exceeding 0.9 under circularly polarized wave excitation.

6. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 1, characterized in that The dielectric substrate is made of high-frequency dielectric material with a relative dielectric constant =3.0, the upper surface metal pattern and the lower surface metal plane are both made of full copper.

7. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 1, characterized in that The visual closed-loop control system comprises: Array image acquisition module: contains the metasurface array structure and a camera, used to collect images of all units in the metasurface; The unit angle recognition module includes a computing board and a neural network algorithm. The computing board is connected to the motor control circuit in the unit angle control module and is used to process multiple input substrate unit images in parallel. The neural network algorithm is used to simultaneously identify the metal pattern type and rotation angle of the substrate unit. Unit angle control module: Contains motor control circuit and motor control algorithm, used to drive the motor to adjust the unit substrate to the final rotation angle according to the angle difference.

8. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 7, characterized in that The camera is electrically connected to the computing board, and the computing board is electrically connected to the motor control circuit, forming a closed-loop link of image acquisition-recognition-control.

9. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 7, characterized in that The computing board supports parallel processing of multi-unit images, and the neural network algorithm can simultaneously identify the metal pattern type and real-time rotation angle of the unit, adapting to the GPU parallel computing architecture.

10. A reconfigurable metasurface device with broadband and polarization-independent characteristics as claimed in claim 7, characterized in that The workflow of the visual closed-loop control system includes: a camera acquires an image of each substrate unit on the metasurface; a neural network algorithm of a unit angle recognition module identifies the angle of the substrate unit and compares the difference between the preset angle and the recognized angle; based on the angle difference, a unit angle control module is used to complete motor rotation control, and the motor rotation is stopped after reaching the target angle.

Images