A switchable absorber and surface wave mode programmable metasurface antenna for wireless communication

Abstract

The application relates to a switchable absorber and vortex wave mode programmable metasurface antenna for wireless communication, and a metasurface unit structure of the metasurface antenna is in a sandwiched sandwich configuration and is composed of a three-layer metal layer separated by two different three-layer dielectric layers, and comprises a top metal pattern layer, a top dielectric substrate layer, a middle metal floor layer, a middle dielectric substrate layer, a bottom dielectric substrate layer and a bottom direct current bias network layer arranged in sequence from top to bottom. The independent control of PIN diodes in each unit structure can realize multi-bit amplitude coding and 1-bit phase coding on the same platform, so that the application has the ability to realize the reconfigurable functions of multi-stage amplitude adjustment, beam deflection and vortex wave generation, and can serve the application requirements of signal dynamic regulation and beam flexible shaping in future wireless communication systems.

Description

Technical Field

[0001] This application belongs to the field of wireless communication and microwave programmable metasurface technology, specifically relating to a programmable metasurface antenna with switchable absorption and vortex wave modes for wireless communication. Background Technology

[0002] The demand for dynamic electromagnetic wavefront control capabilities is growing in fields such as wireless communication systems, especially in scenarios involving beamforming, signal coverage, and interference suppression, where microwave control devices with flexible and reconfigurable capabilities are urgently needed. In the microwave band, to enable metasurfaces to transition from "single device, single function" to "single device, multi-functional integration," existing technologies have proposed a technical path of constructing reconfigurable metasurfaces by integrating semiconductor active devices. These metasurface structures achieve digital programming control of the electromagnetic response through the operating states of electrically (or optically) controlled active devices, thereby driving the rapid development of programmable metasurfaces as a cutting-edge field.

[0003] In 2014, Professor Cui Tiejun's team first proposed the concepts of coded metamaterials and digital metamaterials, providing a theoretical framework for the realization of programmable metasurfaces. The core technology of this type of metasurface lies in combining the discrete response states (such as phase and amplitude) of the basic unit of the metasurface with digital encoding (e.g., 0 and 1 in 1-bit), and using digital control circuits such as field-programmable gate arrays (FPGAs) to achieve real-time dynamic control of electromagnetic waves through programming. The proposal of this technical solution marks a significant shift in metasurface research from passive static design to active dynamic reconstruction, significantly improving the degree of freedom in electromagnetic wave manipulation.

[0004] Compared to traditional metasurfaces, whose functions are fixed after manufacturing, programmable metasurfaces offer the following technological advantages: by discretizing and digitally encoding the electromagnetic response of each unit, the complexity of structural design can be effectively reduced and the control efficiency improved; on the same metasurface unit structure, multiple functions such as beam deflection, polarization conversion, vortex beam generation, and holographic imaging can be achieved in real time and flexibly switched at the system level through software programming, exhibiting good environmental adaptability and functional reconfigurability; and they have natural compatibility with digital circuits and algorithm systems, facilitating the subsequent integration of cutting-edge technologies such as artificial intelligence and software-defined systems.

[0005] Based on the aforementioned advantages, programmable metasurface technology has developed rapidly in recent years, achieving a key leap from proof-of-concept to engineering applications in fields such as high-speed wireless communication, high-resolution sensing and imaging, adaptive electromagnetic stealth, and microwave energy management. Particularly in the field of wireless communication, as one of the core hardware carriers of reconfigurable smart reflector (RIS) technology, it has shown promising engineering application prospects in areas such as signal coverage enhancement, multipath channel modulation, and beamspace multiplexing.

[0006] From the perspective of functional implementation mechanisms, existing programmable metasurfaces mainly achieve their diverse functions by controlling the wavefront phase or spatial amplitude. Phase-encoded metasurfaces, based on electromagnetic wavefront manipulation theories such as the generalized Snell's law, discretize and encode the phase response of the unit structure, enabling functions such as dynamic anomalous beam deflection, polarization conversion, vortex beam generation, and holographic imaging. Amplitude-controlled metasurfaces focus on modulating the spatial distribution of electromagnetic wave energy. By controlling the transmission, reflection, or absorption coefficients of the control unit, they achieve programmable allocation of electromagnetic energy. Their main functions include higher-order diffraction beam manipulation, dynamic reduction of radar cross section (RCS), and switchable absorption modes. Among these functions, absorption, beam deflection, and vortex wave generation are three important aspects of research on the applications of programmable metasurfaces. Absorbers are used to absorb and dissipate incident electromagnetic wave energy; beam deflection is achieved by manipulating the spatial propagation direction of reflected or transmitted electromagnetic waves; and vortex waves containing orbital angular momentum (OAM) can control the amplitude and phase distribution of reflected or transmitted waves by changing the topological charge number.

[0007] However, existing programmable metasurfaces for applications such as wireless communication mostly focus on single functional dimensions such as amplitude modulation or phase modulation, lacking engineering solutions for real-time switching between absorption and vortex wave operation modes. This makes it difficult to meet the dual requirements of dynamic interference suppression and channel capacity enhancement in complex communication scenarios. Therefore, how to achieve joint amplitude and phase modulation on the same metasurface has become an important research direction. Summary of the Invention

[0008] The purpose of this application is to overcome the shortcomings of the prior art and provide a programmable metasurface antenna for wireless communication that can switch between absorbing and vortex wave modes. By independently controlling the PIN diodes in each unit structure, the metasurface can realize multi-bit amplitude encoding and 1-bit phase encoding on the same platform, thereby having the ability to realize reconfigurable functions such as multi-level amplitude adjustment, beam deflection and vortex wave generation, which can serve the application needs of dynamic signal control and flexible beamforming in future wireless communication systems.

[0009] The technical problem solved by this application is achieved through the following technical solution: A programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes is disclosed. The metasurface unit structure of the antenna has a sandwich configuration, consisting of three metal layers separated by two different three-layer dielectric layers. The antenna comprises, from top to bottom, a top metal pattern layer, a top dielectric substrate layer, a middle metal ground layer, a middle dielectric substrate layer, a bottom dielectric substrate layer, and a bottom DC bias network layer. The top metal pattern layer includes a "U"-shaped structure and a "cross"-shaped structure. To provide reconfigurable controllability to the unit structure, PIN diodes are integrated on the two arms of the "U"-shaped structure. By applying different bias voltages, the state of the PIN diodes in the control structure is controlled, enabling the unit structure to achieve different reconfigurable functions. The middle dielectric substrate layer connects the bottom DC bias network layer and the metasurface structure, thereby providing a bias voltage for the PIN diodes.

[0010] Furthermore, the top and bottom dielectric substrate layers are made of F4B material with a relative permittivity of 3.5 and a loss tangent of 0.001; the middle dielectric substrate layer is made of Rogers RO4450F material with a relative permittivity of 3.52 and a loss tangent of 0.004; the thicknesses of the top, bottom, and middle dielectric substrate layers are respectively... h 1 = 3 mm h 2 = 0.2 mm and h 3 = 0.1 mm.

[0011] Furthermore, the top metal pattern layer, the middle metal ground layer, and the bottom DC bias network layer all employ a thickness of [missing information]. h 4 is 0.018 mm, and has a conductivity of 5.8 × 10⁴. 7 Made of copper with S / m; The inner and outer radii of the bottom circular portion of the "U"-shaped structure are respectively... r 2 = 4 mm, r 1 = 5 mm; the length of the two arms of the "U" shaped structure is w 2 = 5.2 mm, the length reserved for welding the PIN diode in the "U" shaped structure is g = 1.2 mm; the "cross-shaped" structure consists of two rectangles, with lengths of respectively l 1 = 5 mm l 2 = 6 mm, width is w 3 = 1.5 mm, the "cross-shaped" structure is shifted upwards relative to the center. w 4 = 1.5 mm.

[0012] Furthermore, the PIN diodes are PIN-1 and PIN-2 diodes, model number SkyworksSMP1321-040LF.

[0013] Moreover, in addition to supporting binary switching between the two basic states of total reflection and total absorption of the metasurface, the PIN diode can also adjust its reflection amplitude to the intermediate state through fine bias control, so as to achieve continuous adjustment of multi-level reflection amplitude. The metasurface antenna is based on the active control mechanism of PIN diodes. The state of the PIN diodes in each unit structure is controlled by FPGA. It can realize multi-bit amplitude encoding and 1-bit phase encoding on the same structure, thus having reconfigurable functions of multi-level amplitude adjustment, beam deflection and vortex wave generation. The PIN-1 and PIN-2 diodes always operate synchronously with the same resistance value. In amplitude encoding mode, the entire metasurface array is globally controlled by a unified DC bias voltage. In phase encoding mode, each unit structure in the array is independently electrically controlled and addressed. By discretizing the phase response of each unit structure, complex dynamic wavefront modulation functions such as beam deflection and vortex wave generation are realized.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The programmable metasurface antenna of the present invention can realize multi-bit amplitude encoding and 1-bit phase encoding on the same platform, and has flexible function configuration, and can realize multiple reconfigurable functions such as multi-level reflection amplitude adjustment, beam deflection and vortex beam generation respectively.

[0015] 2. In amplitude encoding mode, this invention can not only realize binary switching between two working states of total reflection and near-total absorption, but also realize multi-level continuous adjustment of intermediate reflection amplitude through fine bias control, which significantly improves the degree of freedom of amplitude control.

[0016] 3. This invention achieves independent addressing and control of the structural state of each basic unit in the metasurface by means of back-side wiring design, fully releasing its dynamic regulation potential and providing technical support for high-precision beamforming and spatial multiplexing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the metasurface unit structure of the present invention; Figure 2 For the present invention in x -Amplitude and phase response results under LP wave incidence (amplitude encoding); Figure 3 For the present invention in x -Amplitude response characteristics under LP wave incidence; Figure 4 For the present invention in x -Amplitude and phase response results under LP wave incident (phase encoding); Figure 5 This is a simulation result diagram showing the vortex beam generation function implemented in this invention; Figure 6 This is a physical illustration of the present invention; Figure 7 The figures show the simulation and experimental results of the beam scanning function of this invention. Figure 8 The figure shows the experimental results of the vortex wave generation function of this invention. Detailed Implementation

[0018] The present application will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present application.

[0019] like Figure 1 As shown, where Figure 1 (a), 1(b), and 1(c) represent the metasurface unit structure (periodic) of the metasurface antenna of the present invention, respectively. p Perspective, front, and side views (12 mm), revealing a programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes. Its innovation lies in the following: the metasurface's unit structure is a sandwich configuration, consisting of three metal layers separated by two different three-layer dielectric layers. These include, from top to bottom, a top metal pattern layer, a top dielectric substrate layer, a middle metal ground plane layer, a middle dielectric substrate layer, a bottom dielectric substrate layer, and a bottom DC bias network layer. The top metal pattern layer includes "U"-shaped and "cross"-shaped structures. To provide reconfigurable controllability to the unit structure, PIN diodes are integrated on the two arms of the "U"-shaped structure. By applying different bias voltages, the state of the PIN diodes in the control structure is controlled, enabling the unit structure to achieve different reconfigurable functions. The middle dielectric substrate layer connects the bottom DC bias network layer and the metasurface structure, thereby providing bias voltage for the PIN diodes.

[0020] The top and bottom dielectric substrate layers are made of F4B material with a relative permittivity of 3.5 and a loss tangent of 0.001. The middle dielectric substrate layer is made of Rogers RO4450F material with a relative permittivity of 3.52 and a loss tangent of 0.004. The thicknesses of the top, bottom, and middle dielectric substrate layers are respectively... h 1 = 3 mm h 2 = 0.2 mm and h 3 = 0.1 mm.

[0021] The top metal pattern layer, the middle metal ground layer, and the bottom DC bias network layer all adopt a thickness of [missing information]. h 4 is 0.018 mm, and has a conductivity of 5.8 × 10⁴. 7 Made of copper with S / m; The inner and outer radii of the bottom circular portion of the "U"-shaped structure are respectively... r 2 = 4 mm, r 1 = 5 mm; the length of the two arms of the "U" shaped structure is w 2 = 5.2 mm, the length reserved for welding the PIN diode in the "U" shaped structure is g = 1.2 mm; the "cross-shaped" structure consists of two rectangles, with lengths of respectively l 1 = 5 mm l 2 = 6 mm, width is w 3 = 1.5 mm, the "cross-shaped" structure is shifted upwards relative to the center. w 4 = 1.5 mm.

[0022] The PIN diodes are PIN-1 and PIN-2 diodes, model Skyworks SMP1321-040LF. In addition to supporting binary switching between the two basic states of total reflection and total absorption of the metasurface, the PIN diodes can also adjust the reflection amplitude to the intermediate state through fine bias control to achieve continuous adjustment of multi-level reflection amplitude. The metasurface antenna is based on the active modulation mechanism of PIN diodes. The state of the PIN diodes in each unit structure is controlled by FPGA. It can realize multi-bit amplitude encoding and 1-bit phase encoding on the same structure, thus having reconfigurable functions such as multi-level amplitude adjustment, beam deflection and vortex wave generation.

[0023] Figure 1 (d) shows the equivalent circuit model of the PIN diode, which consists of a fixed capacitor (C = 0.15 pF) and a variable resistor ( R = 1 ~ 10 k The units are connected in parallel. Regarding the method of controlling the unit state, there are differences between experimental testing and full-wave electromagnetic simulation: in the experiment, different bias voltages are applied to control the state of the PIN diodes in each unit; in the simulation, to simplify the model and improve computational efficiency, the following method is directly used... Figure 1 (d) shows a lumped variable resistor model to simulate the unit response under different bias voltages.

[0024] The following studies all focus on x-LP wave incident case, and the two PIN diodes in each unit structure always work synchronously and with the same resistance value; in amplitude encoding mode, the entire metasurface array is globally controlled by a unified DC bias voltage; unlike amplitude encoding, phase encoding mode requires independent electronic control addressing for each unit in the array. By discretizing the phase response of each unit structure, complex dynamic wavefront control functions such as beam deflection and vortex wave generation can be further realized.

[0025] Explanation of the multi-level amplitude adjustment function in metasurface amplitude encoding mode when x When a linearly polarized (x-LP) wave is incident perpendicularly along the -z axis onto the programmable metasurface, the simulation results of the reflection amplitude and reflection phase of the unit structure are as follows: Figure 2 As shown in (a)~2(d), when the equivalent resistance of the two PIN diodes in the unit structure changes from 1... Simultaneously increase to 10 k During the process, the reflection amplitude of the unit first decreases and then increases, that is, it gradually transitions from the initial high reflection state to a near-perfect absorption state, and then returns to the high reflection state.

[0026] Specifically, it can be divided into two stages: in 1 Up to 60 Within a given resistance range, the reflection amplitude gradually decreases as the resistance value increases, but during this process, the reflection phase remains essentially constant; when the resistance value increases from 70... Continue to increase to 10 k At this point, the reflection amplitude gradually increases with the increase of the resistance value, while the reflection phase only fluctuates slightly and remains stable overall. The simulation results clearly demonstrate that the designed metasurface unit structure, by adjusting the equivalent resistance, achieves continuously adjustable multi-level reflection amplitude switching between high reflection and perfect absorption states, and the reflection phase remains highly stable throughout the entire control process. This "adjustable amplitude, constant phase" response characteristic verifies that the unit structure possesses the ability to achieve high-performance multi-level amplitude encoding control, laying the foundation for subsequent construction of programmable metasurface arrays and dynamic amplitude control.

[0027] To illustrate the multi-level amplitude adjustment capability of the above-mentioned unit structure, this embodiment selects 1, 10, 20, 40, and 60. Five different resistance values ​​( R ), used to characterize the absorbance of the metasurface ( A = 1 - | r xx | 2This can be interpreted as a stepwise change in the reflection amplitude. Within the operating frequency band of 10.4 ~ 10.6 GHz, these five resistance values ​​correspond to five distinctly different reflection states: total reflection, 0.8, 0.6, 0.4, and total absorption. Figure 3 (a) gives the time when x -LP wave perpendicular incidence condition, metasurface absorbance curves corresponding to five different resistance values. The results clearly show that by adjusting the equivalent resistance values ​​of PIN-1 and PIN-2 ( R The absorption intensity of the unit can be significantly altered, thereby achieving continuous, programmable multi-level control between high reflection and full absorption states. To further verify the actual beam control capability of the metasurface in amplitude coding mode, this embodiment further analyzes the intensity response of the scattered beam. Figure 3 (b) shows the resistance value at a frequency of 11.5 GHz when the resistance is set to 1. and 60 Simulation results of the two-dimensional far-field radiation pattern of the amplitude-coded metasurface array are presented. Under two resistive configurations, the main reflected beam points towards the spatial direction (0°, 0°), corresponding to total reflection and total absorption states, respectively. The conclusions obtained are consistent with... Figure 3 The results in (a) are consistent with the results of judging whether the metasurface is in a state of total reflection or total absorption by using the absorption rate.

[0028] In summary, both the change in absorption rate and the intensity response of the reflected beam consistently demonstrate that the designed metasurface can achieve good multi-level reflection amplitude adjustment, effectively expanding the degree of freedom and flexibility of electromagnetic wave amplitude control.

[0029] Analysis of the relevant functions of metasurfaces in phase encoding mode like Figure 4 As shown in (a) and 4(b), in the frequency band of 10.2 ~ 11.2 GHz, when the PIN diode is at 1 and 10 k In the resistive state, the phase difference between the two reflections remains stable at around 180°, with fluctuations not exceeding ±10°. Simultaneously, the corresponding reflection amplitudes remain essentially consistent in both states. These results demonstrate that the designed metasurface unit can provide a stable phase difference close to 180° while maintaining similar amplitudes, thus possessing the key conditions for achieving efficient 1-bit phase encoding. Based on the above unit response characteristics, this invention uses the resistance value... R = 10 k and R = 1 They are defined as binary phase codes "0" and "1" respectively, and are used as the basic coding units for subsequent phase coding control.

[0030] This invention further demonstrates the functionality of the metasurface in vortex beam generation. At a frequency of 10.8 GHz, the metasurface array can generate an orbital angular momentum (OAM) beam propagating along the spatial direction (0°, 0°) and carrying a preset topological charge number. According to vortex wave generation theory, for the metasurface array to reflect a vortex beam with a specific topological charge number, the phase distribution of each element must satisfy the following relationship: (1) Since the metasurface in this invention only supports 1-bit phase resolution, i.e., two discrete phase states, the above continuous phase distribution needs to be quantized into two discrete values, and their correspondence is as follows: (2) Based on equations (1) and (2), the continuous phase distribution can be mapped to a discrete “0” or “1” encoding sequence, thereby determining the metasurface array encoding pattern required to generate the target vortex beam.

[0031] Figure 5 (a), (b), (e), and (f) present the amplitude and phase distribution results of the metasurface array generating a vortex beam pointing to (0°, 0°) at a frequency of 10.8 GHz, where the topological charge numbers are respectively... l = +1 and l = +2. Simulation results show that for l A vortex beam with amplitude equal to +1 exhibits a typical annular distribution, meaning the energy is zero at the center, surrounded by a bright ring. Correspondingly, its phase distribution shows a continuous spiral phase change covering 360°. For l In the +2 mode, the range of helical phase variation extends to 720°. These results fully validate the feasibility of the metasurface in generating axial vortex beams, laying a technical foundation for further dynamic deflection control of vortex beams.

[0032] By combining vortex beam generation technology with beam scanning and control technology, dual coordinated control of the topological charge number and propagation direction of vortex beams can be achieved on the same metasurface platform, providing an effective technical path for the dynamic generation of multi-angle, multi-mode vortex electromagnetic waves. Based on a metasurface with 1-bit phase encoding, this invention introduces phase compensation technology to deflect the vortex beam to a preset direction. The required phase distribution must satisfy the following relationship: (3) To deflect the vortex beam carrying OAM to a predetermined direction, the overall phase distribution required by the metasurface array should satisfy the linear superposition of equations (1) and (3): (4) Similar to the quantization method in equation (2), the phase Φ calculated in equation (4) also needs to be converted using the following two piecewise equations. OAM_BEAM-SCANING Quantized to 1-bit discrete state: (5) Figure 5 (c) and 5(g) give the topological charge number at an operating frequency of 11.1 GHz. l Simulation results of amplitude and phase distribution of a vortex beam deflected to 30° with a value of +1. As shown in the figure, after deflection control, the energy center of the vortex beam shifts by 30° accordingly, while its phase distribution still maintains the complete 360° spiral phase change characteristics, indicating that the topological characteristics of the vortex beam are effectively maintained during the deflection process. Figure 5 (d) and 5(h) give the values ​​at 10.9 GHz. l The result of deflecting a +2 vortex wave to a 45° azimuth angle shows that its vortex center shifts by 45° and its phase rotation extends to 720°. These results demonstrate that the metasurface based on 1-bit phase encoding combined with phase compensation technology can control the deflection of vortex beams with different topological charge numbers in a preset direction at different operating frequencies. After deflection, the orbital angular momentum characteristics of the vortex beam remain consistent with those of the 0° reflected vortex wave in both amplitude and phase. This verifies the effectiveness and reliability of the metasurface in the dynamic deflection of vortex beams.

[0033] To experimentally verify the performance of the programmable metasurface described in this invention, a sample metasurface array consisting of 16×16 metasurface units was fabricated using printed circuit board (PCB) technology. This sample integrates 512 PIN diodes and has an overall physical size of 192×192 mm. 2 Its front view is as follows Figure 6 As shown. To verify the beam scanning capability of the proposed metasurface, this invention designs and employs along... x The phase encoding sequence of the axis, 0011001100110011, was used for corresponding simulation and experimental testing. Figure 7 (a)~(b) show the simulated and measured far-field radiation patterns under this encoding, respectively. It can be clearly observed that... x Under -LP wave incidence, the measured reflected beam direction is approximately 35°, which is basically consistent with the simulated beam direction. The slight deviation between the simulation and measured results can be attributed to factors such as machining tolerances, welding effects, and calibration errors of the experimental measurement system. These results effectively verify the engineering feasibility of the described metasurface in beam scanning control.

[0034] Figure 8 (a)~ Figure 8 (d) gives the topological charge number respectivelyl The measured amplitude and phase distribution of the vortex beam at deflection angles of 0° and 30° under the +1 condition are as follows: For the 0° deflection, the vortex wave exhibits a complete 360° phase change, with a circular distribution in the high-amplitude region and a relatively low amplitude in the central region. Similarly, the vortex wave at a 30° deflection also exhibits a complete 360° phase change and a ring-shaped amplitude distribution with a lower central amplitude. The higher amplitude observed at the sample edge may be due to the fact that the aperture of the test horn antenna was slightly smaller than the sample size during the near-field measurement of the reflected wave, resulting in measurement errors in the reflected wave collected by the probe near the edge of the metasurface. In addition, the high amplitude phenomenon at the edge may also be affected by factors such as the limited scanning aperture size, diffraction phenomena at the sample edge, multiple reflections between the probe and the sample, system measurement errors, and manufacturing tolerances. In summary, the experimental results verify the effectiveness of the metasurface in the dynamic generation of vortex beams.

[0035] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes, characterized in that: The metasurface antenna has a sandwich-like structure, consisting of three metal layers separated by two different three-layer dielectric layers. These include, from top to bottom, a top metal pattern layer, a top dielectric substrate layer, a middle metal ground layer, a middle dielectric substrate layer, a bottom dielectric substrate layer, and a bottom DC bias network layer. The top metal pattern layer includes "U"-shaped and "cross"-shaped structures. To provide the unit structure with reconfigurable controllability, PIN diodes are integrated on the two arms of the "U"-shaped structure. By applying different bias voltages, the state of the PIN diodes in the control structure is controlled, enabling the unit structure to achieve different reconfigurable functions. The middle dielectric substrate layer connects the bottom DC bias network layer and the metasurface structure, thereby providing bias voltage for the PIN diodes.

2. The programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes according to claim 1, characterized in that: The top and bottom dielectric substrate layers are made of F4B material with a relative permittivity of 3.5 and a loss tangent of 0.

001. The middle dielectric substrate layer is made of Rogers RO4450F material with a relative permittivity of 3.52 and a loss tangent of 0.

004. The thicknesses of the top, bottom, and middle dielectric substrate layers are respectively... h 1 = 3 mm h 2 = 0.2 mm and h 3 = 0.1 mm.

3. The programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes according to claim 1, characterized in that: The top metal pattern layer, the middle metal ground layer, and the bottom DC bias network layer all adopt a thickness of [missing information]. h 4 is 0.018 mm, and has a conductivity of 5.8 × 10⁴. 7 Made of copper with S / m; The inner and outer radii of the bottom circular portion of the "U"-shaped structure are respectively... r 2 = 4 mm, r 1 = 5 mm; the length of the two arms of the "U" shaped structure is w 2 = 5.2 mm, the length reserved for welding the PIN diode in the "U" shaped structure is g = 1.2 mm; the "cross-shaped" structure consists of two rectangles, with lengths of respectively l 1 = 5 mm l 2 = 6 mm, width is w 3 = 1.5 mm, the "cross-shaped" structure is shifted upwards relative to the center. w 4 = 1.5 mm.

4. The programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes according to claim 1, characterized in that: The PIN diodes are PIN-1 and PIN-2 diodes, model number SkyworksSMP1321-040LF.

5. The programmable metasurface antenna for wireless communication with switchable absorbing and vortex wave modes according to claim 1, characterized in that: In addition to supporting binary switching between the two basic states of total reflection and total absorption of the metasurface, the PIN diode can also adjust its reflection amplitude to the intermediate state through fine bias control, so as to achieve continuous adjustment of multi-level reflection amplitude. The metasurface antenna is based on the active control mechanism of PIN diodes. The state of the PIN diodes in each unit structure is controlled by FPGA. It can realize multi-bit amplitude encoding and 1-bit phase encoding on the same structure, thus having reconfigurable functions of multi-level amplitude adjustment, beam deflection and vortex wave generation. The PIN-1 and PIN-2 diodes always operate synchronously with the same resistance value. In amplitude encoding mode, the entire metasurface array is globally controlled by a unified DC bias voltage. In phase encoding mode, each unit structure in the array is independently electrically controlled and addressed. By discretizing the phase response of each unit structure, complex dynamic wavefront modulation functions such as beam deflection and vortex wave generation are realized.

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