Polarization multiplexing coding metasurface antenna array

Abstract

The invention provides a polarization multiplexing encodable metasurface antenna array, comprising a dual-polarized antenna array which is composed of dual-polarized antenna units arranged in a two-dimensional period and is used for exciting orthogonal polarized waves respectively; a polarization beam controller array; the feed source antenna is located right in front of the geometric center of the dual-polarized antenna array; and the digital voltage control module is connected with the polarization beam controller array through an inner-layer circuit so as to realize dynamic regulation and control of the polarization mode and the phase state of the dual-polarization antenna unit. On a polarization processing structure, a double-feeding point and bridge cross transmission mode is adopted, orthogonal overturning of horizontal polarization and vertical polarization is achieved on a physical layer, in the aspect of polarization control precision, a special V1 signal control matching / isolation state is set, polarization control freedom is newly increased, and in the aspect of orthogonal signal receiving capacity, the polarization control precision is improved. Any polarization is covered without a blind area, and the problem of multipath environment signal fading is effectively eliminated.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a polarization multiplexing and codable metasurface antenna array. Background Art

[0002] In recent years, codeable metasurfaces have opened up new avenues for the dynamic control of electromagnetic beams. Unlike traditional metasurfaces that rely on fixed phase gradients, codeable metasurfaces can flexibly switch electromagnetic wave states through different digital coding sequences. Their design concept is derived from the concept of bits in computer coding, using binary coding to control the unit phase state, thereby achieving digital control. As the number of bits increases, the codeable metasurface can provide more phase states, improving the freedom and precision of beam steering. Due to their low cost and simple structure, codeable metasurfaces have broad application prospects in the field of electromagnetic wave control and can be widely used in imaging, perception, communications, radar, and other fields.

[0003] With the increasing complexity of the environment and the diversification of functionalities, metasurfaces that can only control a single electromagnetic dimension are no longer able to meet practical needs. Multi-channel electromagnetic wave multiplexing technology has gradually become a research focus, and composite metasurface architectures with multi-dimensional control capabilities have emerged. Polarization multiplexing is a typical method. It uses multiple polarization channels as independent information transmission channels, effectively adapting to different channel conditions and multipath propagation environments, reducing the impact of multipath effects and signal fading, and improving the system's fault tolerance and anti-interference capabilities. Polarization-multiplexing metasurfaces typically integrate RF switches or diodes in the antenna radiating surface or feed network. The on-off switching of RF devices changes the surface current distribution and radiation direction, thereby controlling the polarization state of the metasurface. However, these electrically adjustable components often introduce additional losses and increase the design complexity of the feed network. Therefore, how to design polarization-multiplexing coded metasurfaces with high efficiency and low polarization crosstalk remains a key challenge in this research field.

[0004] In the prior art, codeable metasurface antenna arrays mainly achieve dynamic adjustment of electromagnetic wave parameters by integrating adjustable elements into antenna units. For example, patent document CN118554177A discloses a multi-modal integrated dynamic codeable metasurface antenna array. This technology achieves switching between signal receiving and transmitting states and absorption states through a combination of a 2-bit codeable metasurface antenna array, a feed antenna, a switch device array, and a digital voltage control module, thereby enhancing beamforming capabilities. However, this technology mainly regulates single-polarized electromagnetic waves. Its core problem is that it cannot achieve polarization twisting and cannot effectively process multi-polarized signals.

[0005] Specifically, the antenna unit in patent document CN118554177A uses a single-port feeding scheme and can only respond to incident waves with a fixed polarization direction. The polarization state of the reflected wave is exactly the same as the incident wave. The RFC port of the switch device is directly connected to a single feed point. The six-channel design also does not include a cross-coupling path or polarization rotation element, lacking a polarization conversion mechanism. This results in poor adaptability in multi-polarization scenarios. When the incident wave is horizontally polarized, the polarization mismatch prevents effective energy coupling, and the reflected wave remains horizontally polarized, causing vertically polarized receiver signal loss and forming a polarization blind spot. Furthermore, the antenna has weak anti-interference capabilities in multipath scattering environments, making it impossible to utilize orthogonal polarization channels to improve spectral efficiency. Furthermore, the switch devices in its control architecture are functionally limited, connecting only to open / short circuits and 50Ω transmission lines / loads. Polarization processing components such as bridges and inverters are lacking. The control logic also lacks an orthogonal dimension, making it impossible to independently control the polarization state.

[0006] Therefore, there is an urgent need for a polarization-multiplexed, codeable metasurface antenna array that can regulate incident signals at arbitrary polarization angles, eliminate polarization coverage blind spots, and simplify the design of the control network to meet the needs of modern wireless communication systems for high-performance, multi-functional antennas. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention aims to provide a polarization multiplexing and coding metasurface antenna array. In order to achieve the above object, the present invention is implemented through the following technical solution: a polarization multiplexing and coding metasurface antenna array, comprising:

[0008] A dual-polarization antenna array is composed of dual-polarization antenna units arranged in a two-dimensional periodic manner, each of which is provided with an independent horizontal polarization feeding point and a vertical polarization feeding point for respectively exciting orthogonal polarization waves;

[0009] A polarization beam controller array includes controllers corresponding to the number of dual-polarization antenna units, wherein the two RF channels of each controller are connected to the feed points of the corresponding dual-polarization antenna units through metal vias, and each controller includes an inverter, multiple single-pole double-throw switches, multiple single-pole four-throw switches, and a bridge;

[0010] The feed antenna is located in front of the geometric center of the dual-polarized antenna array;

[0011] The digital voltage control module is connected to the polarization beam controller array through an inner layer line, and synchronously drives the single-pole four-throw switch through the C1 and / or C2 control lines to generate a reflection phase state of 0°, 90°, 180°, or 270° to achieve dynamic control of the polarization mode and phase state of the dual-polarization antenna unit, wherein:

[0012] The input and output ends of the inverter are respectively connected to the control pin V1 of the single-pole double-throw switch (13) to achieve simplified circuit control;

[0013] The digital voltage control module switches the polarization matching state and / or polarization isolation state of the metasurface antenna array and the feed antenna by controlling the input level of the inverter. The process is as follows:

[0014] When the inverter input is low, the H / V polarized signals of the dual-polarized antenna array are directly transmitted to the single-pole four-throw switch through their respective channels. After phase adjustment, they are reflected back to the original feeding point, achieving polarization matching between the metasurface antenna array and the feed antenna.

[0015] When the inverter input is high, the H / V polarized signal is coupled through the bridge and then phase modulated through the single-pole four-throw switch, and finally cross-transmitted to the other party's feeding point, realizing polarization isolation between the metasurface antenna array and the feed antenna.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Since the traditional codable metasurface antenna array cannot adjust the polarization of the reflected wave, this leads to blind spots in the polarization coverage control of spatial signals. The receiving end will have poor signal reception in specific orthogonal polarization scenarios. Therefore, the present invention adopts a dual feeding point plus bridge cross-transmission method in the polarization processing structure to realize the orthogonal flipping of horizontal polarization and vertical polarization at the physical layer. In terms of polarization control accuracy, the present invention sets a dedicated V1 signal control matching / isolation state, adds a new degree of freedom for polarization control, and covers any polarization without blind spots in terms of orthogonal signal reception capability, effectively eliminating the problem of multipath environment signal fading.

[0018] 2. Since traditional codable metasurface antenna arrays can only regulate electromagnetic waves incident at a specific polarization angle and cannot regulate signals incident at any polarization angle, the present invention reduces the complexity of the control architecture by using two-line synchronous driving of four switches to simplify the control circuit, so that the present invention has dual-polarization independent response capabilities, can achieve polarization-matched co-polarization reflection and polarization-isolated orthogonal polarization reflection, and achieve a breakthrough solution to the signal coverage problem in multi-polarization environments.

[0019] 3. The present invention can flexibly switch the polarization state through dynamic coding, achieve polarization matching or polarization isolation with the feed source, effectively increase the information transmission channel and improve the channel capacity. At the same time, the metasurface antenna array also has a codable beam scanning function, which controls the direction of the electromagnetic beam through coding, focuses the electromagnetic wave energy, and improves the signal transmission quality and target tracking accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0021] Figure 1 Schematic diagram of the overall structure of the polarization-multiplexed and coded metasurface antenna array proposed in one embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the structure of a dual-polarized antenna unit proposed in one embodiment of the present invention;

[0023] Figure 3 Schematic diagram of the topological connection of the polarization beam controller proposed in one embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the main polarization and cross-polarization simulation directions of the dual-polarization antenna unit proposed in one embodiment of the present invention;

[0025] Figure 5 Schematic diagram of a simulation curve showing how the reflection phase of a dual-polarized antenna unit proposed in one embodiment of the present invention changes with frequency in different phase states;

[0026] Figure 6a Schematic diagram of the encoding method of the polarization-multiplexed codeable metasurface antenna array proposed in one embodiment of the present invention at a frequency of 2.45 GHz with a beam direction of (0°, 0°);

[0027] Figure 6b Schematic diagram of the two-dimensional far-field direction of the polarization-multiplexed coded metasurface antenna array proposed in one embodiment of the present invention at a frequency of 2.45 GHz with a beam direction of (0°, 0°);

[0028] Figure 7a Schematic diagram of the encoding method of the polarization-multiplexed codeable metasurface antenna array proposed in one embodiment of the present invention at a frequency of 2.45 GHz with a beam direction of (60°, 0°);

[0029] Figure 7b This is a schematic diagram of the two-dimensional far-field direction of the polarization-multiplexed and codable metasurface antenna array proposed in one embodiment of the present invention at a frequency of 2.45 GHz when the beam direction is (60°, 0°).

[0030] Description of reference numerals:

[0031] 1. Dual-polarized antenna array; 2. Polarization beam controller array; 3. Digital voltage control module; 4. Feed antenna; 5. Metal parasitic patch; 6. First dielectric substrate; 7. Metal radiating patch; 8. Second dielectric substrate; 9. Metal ground; 10. Horizontal polarization feed point; 11. Vertical polarization feed point; 12. Inverter; 13. Single-pole double-throw switch; 14. Single-pole four-throw switch; 15. Bridge; 16. Field-programmable gate array hardware system; DETAILED DESCRIPTION

[0032] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0033] The present invention will be further described below in conjunction with the accompanying drawings, but this does not limit the present invention.

[0034] As an understanding of the technical concept of the present invention, since the traditional codeable metasurface antenna array can only control electromagnetic waves incident at a specific polarization angle, it cannot control signals incident at any polarization angle. At the same time, the traditional codeable metasurface antenna array cannot adjust the polarization of the reflected wave, which leads to a blind spot in the polarization coverage control of spatial signals, and the receiving end will have poor signal reception in specific orthogonal polarization scenarios.

[0035] Therefore, the present invention proposes a polarization-multiplexed codable metasurface antenna array, which realizes dynamic control of electromagnetic waves incident at any polarization angle through the combination of a dual-polarization antenna array and a polarization beam controller, breaking through the limitation that traditional metasurface antennas can only control electromagnetic waves incident at specific polarization angles; the polarization beam controller can be used to twist the polarization of the reflected wave through encoding, so that the reflected signal has complete coverage in the polarization space. Regardless of the polarization state of the receiving antenna, the system can achieve good signal coverage quality, effectively solving the signal problem of traditional metasurface antennas in specific orthogonal polarization scenarios. The problem of poor reception; the polarization state can be flexibly switched through dynamic coding to achieve polarization matching or polarization isolation with the feed source, effectively increasing the information transmission channel and improving the channel capacity; it has a codable beam scanning function, which controls the direction of the electromagnetic beam through coding, focuses the electromagnetic wave energy, and improves the signal transmission quality and target tracking accuracy; the adopted control architecture simplifies the circuit design, reduces the number of control lines, and reduces the device size required for the digital voltage control module, solving the problem of additional loss and design complexity caused by the integration of RF switches or diodes in the antenna radiation surface or feed network of traditional polarization multiplexing metasurfaces.

[0036] In specific implementation, according to the above technical ideas, such as Figure 1-Figure 2 As shown in the figure, a polarization-multiplexed and coded metasurface antenna array operating in the S band is designed. The array size is 16*16 and the total array size is 960mm*960mm. Compared with other metasurface antenna arrays, it has the advantages of polarization controllable, high beam scanning accuracy, low power consumption, and strong coding capability. It includes:

[0037] A dual-polarized antenna array 1 arranged in a matrix is composed of dual-polarized antenna units arranged in a two-dimensional periodic manner. Each dual-polarized antenna unit is provided with an independent horizontal polarization feeding point 10 and a vertical polarization feeding point 11, which are used to receive and transmit horizontally polarized and vertically polarized electromagnetic wave signals, respectively, to achieve orthogonal polarization wave excitation.

[0038] A polarization beam controller array 2 with a multi-layer structure design includes controllers corresponding to the number of dual-polarization antenna units. The polarization beam controllers are manufactured using printed circuit board technology. The two RF channels of each controller are connected to the horizontal polarization and vertical polarization feed points of the corresponding dual-polarization antenna unit through metal vias. Each controller includes an inverter 12, a plurality of single-pole double-throw switches 13, a plurality of single-pole four-throw switches 14, and a bridge 15.

[0039] The feed antenna 4 is located directly in front of the geometric center of the dual-polarized antenna array 1 and 250 mm from the antenna array surface. This ensures that the feed antenna can uniformly excite the array elements within the effective operating range of the metasurface antenna array, achieving efficient radiation and reception of electromagnetic waves. It also ensures that during beam scanning, the phase compensation of each element can accurately superimpose energy to form a beam pointing in the target direction, thereby improving the stability and reliability of signal transmission. The feed antenna uses a standard gain horn antenna and is fixed by a metal bracket made of aluminum alloy, which has good mechanical strength and lightweight characteristics.

[0040] The digital voltage control module 3 is connected to the polarization beam controller array 2 through the inner layer line, and synchronously drives the single-pole four-throw switch 14 through the two control lines C1 and / or C2 to generate a reflection phase state of 0° or 90° or 180° or 270° to achieve dynamic control of the polarization mode and phase state of the dual-polarization antenna unit. It can be understood that the digital voltage control module preferably adopts a multi-layer PCB design, including an interconnected power management unit, a field programmable gate array hardware system 16 (FPGA control core) and a drive circuit. The power management unit provides two stable power supplies of 3.3V and 5V with a ripple of less than 50mV. The field programmable gate array hardware system adopts the Xilinx Artix-7 series, model XC7A35T, with a clock frequency of 100MHz and a sufficient number of I / O ports to meet the needs of large-scale array control. Among them, the input and output ends of the inverter 12 are respectively connected to the control pins V1 of the two single-pole double-throw switches 13, so as to achieve simultaneous control of the states of the two single-pole double-throw switches 13 through one control line, thereby simplifying the circuit control;

[0041] The digital voltage control module 3 switches between the polarization matching state and / or polarization isolation state of the metasurface antenna array and the feed antenna 4 by controlling the input level of the inverter 12. It can be understood that the principle is as follows: based on the field programmable gate array hardware system, the voltage levels of pins V1, C1, and C2 are controlled through preset coding logic, thereby achieving dynamic regulation of the polarization mode and phase state of the dual-polarized antenna unit. Specifically, the digital voltage control module outputs three sets of independent control signals through the field programmable gate array hardware system 16: the V1 signal is branched through the inverter to control the SP2T switch group to achieve polarization matching / isolation switching; the C1 / C2 signals drive four SP4T switches in parallel to achieve four-phase state selection. The combined encoding of these three sets of signals synchronously completes dual polarization and phase control at the unit level, achieving low-power dynamic beam scanning. The field programmable gate array hardware system integrates a beam steering algorithm that can adjust the polarization and phase state of each unit in real time according to the preset scanning mode or external instructions. The process is as follows: when the inverter input is low, the H / V polarized signals of the dual-polarized antenna array are directly transmitted to the single-pole four-throw switch through their respective channels, and are reflected back to the original feeding point after phase adjustment, thereby realizing polarization matching between the metasurface antenna array and the feed antenna; when the inverter input is high, the H / V polarized signals are coupled through the bridge and then phase modulated through the single-pole four-throw switch, and finally cross-transmitted to the other party's feeding point, thereby realizing polarization isolation between the metasurface antenna array and the feed antenna.

[0042] Specifically: when the inverter input is low, the signal of the horizontal polarization feed point enters through the RFC input channel of the first single-pole double-throw switch, is transmitted from the RF1 output channel to the first single-pole four-throw switch, and then reflected back to the horizontal polarization feed point; the signal of the vertical polarization feed point enters through the RFC input channel of the second single-pole double-throw switch, is transmitted from the RF1 output channel to the second single-pole four-throw switch, and then reflected back to the vertical polarization feed point, thereby realizing the polarization matching between the metasurface antenna array and the feed antenna; when the inverter input is high, the signal of the horizontal polarization feed point enters through the RFC input channel of the first single-pole double-throw switch, is transmitted from the RF1 output channel to the second single-pole four-throw switch, and then reflected back to the vertical polarization feed point. The signal enters the RFC input channel of the double-throw switch, is transmitted to the bridge from the RF2 output channel, is output from the RF1 output channel of the second single-pole double-throw switch after coupling through the bridge, and is reflected to the vertical polarization feed point through the second single-pole four-throw switch; the signal of the vertical polarization feed point enters the RFC input channel of the second single-pole double-throw switch, is transmitted to the bridge from the RF2 output channel, is output from the RF1 output channel of the first single-pole double-throw switch after coupling through the bridge, and is reflected to the horizontal polarization feed point through the first single-pole four-throw switch, thereby realizing polarization isolation between the metasurface antenna array and the feed antenna 4.

[0043] Based on the above technical concepts, it should be noted that in practical applications, the polarization-multiplexed codeable metasurface antenna array proposed in this invention can dynamically adjust the beam direction and polarization characteristics according to communication requirements. For example, in mobile communication scenarios, beam pointing can be adjusted in real time based on user location changes; in anti-interference communications, polarization control can improve signal isolation; and in multi-user MIMO systems, polarization multiplexing can improve spectrum utilization efficiency.

[0044] The polarization-multiplexed, codeable metasurface antenna array proposed in this embodiment achieves joint polarization and phase control through the tight integration of dual-polarization antenna units and polarization beam controllers, significantly enhancing the system's flexibility and adaptability. Compared to traditional reflectarray antennas, this invention offers higher spectrum efficiency and greater environmental adaptability, making it particularly suitable for modern wireless communication systems requiring dynamic beam steering.

[0045] like Figure 3 As shown, in one embodiment of the present invention, each controller is composed of an inverter, two single-pole double-throw (SP2T) switches (SW1 and SW2), four single-pole four-throw (SP4T) switches and a bridge.

[0046] The RFC channel of SW1 is connected to the H-pol feed point (horizontally polarized feed point) of the dual-polarized antenna element via a metal via. The RF1 output channel is connected to an SP4T switch, and the RF2 output channel is connected to the input of the bridge. The RFC channel of SW2 is connected to the V-pol feed point (vertically polarized feed point) of the dual-polarized antenna element via a metal via. The RF1 output channel is connected to the output of the bridge, and the RF2 output channel is connected to another SP4T switch. The input and output of the inverter are connected to the control pin V1 of SW1 and SW2, respectively, to achieve voltage level inversion and compensate for voltage differences caused by the symmetrical layout of the devices. A single control line can simultaneously control both SP2T switches, simplifying the circuit. When the inverter input is low, the H / V polarized signals are directly transmitted to the SP4T switch through their respective channels, and are reflected back to the original feeding point after phase adjustment. At this time, the polarization of the metasurface antenna array and the feed antenna are matched; when the inverter input is high, the H / V polarized signals are coupled through the bridge, and then phase modulated through the SP4T switch, and finally cross-transmitted to the other party's feeding point. At this time, the polarization of the metasurface antenna array and the feed antenna are isolated.

[0047] Each SP4T switch has an RFC input channel and four output channels: RF1, RF2, RF3, and RF4. The connection length of the RF1 output channel is The RF2 output channel is connected to an open line with a length of a, and the RF3 output channel is connected to an open line with a length of The RF4 output channel is connected to a shorted circuit of length a. By controlling the voltage levels of pins C1 and C2, the connectivity between the RFC input channel and the four output channels can be switched, generating four reflected phase states. The control pins of the four SP4T switches are interconnected via an inner circuit, allowing the states of all four switches to be controlled synchronously using only two control lines. This architecture significantly reduces system complexity, the number of control lines, and the device size required for the digital voltage control module.

[0048] In one embodiment of the present invention, the single-pole four-throw switch 14 generates the above-mentioned four different reflection phase states by controlling the levels of C1 and C2. The specific dynamic control correspondence is as follows: when C1 is at a high level "1" and C2 is at a low level "0", the generated reflection phase is 180°; when C1 is at a low level "0" and C2 is at a high level "1", the generated reflection phase is 270°; when C1 and C2 are both at a high level "1", the generated reflection phase is 0°; and when C1 and C2 are both at a low level "0", the generated reflection phase is 90°, where 0 and 1 represent low level and high level, respectively.

[0049] Furthermore, when the level values of C1 and C2 are combined to be "10", the transmission state of the SP4T switch (single-pole four-throw switch 14) is RFC-RF1, and the reflection phase of the dual-polarized antenna unit is adjusted to 180°; when the level values of C1 and C2 are combined to be "01", the transmission state of the SP4T switch (single-pole four-throw switch 14) is switched to RFC-RF2, and the reflection phase is correspondingly changed to 270°; if the level values of C1 and C2 are both high level "11", the SP4T switch (14) enters the RFC-RF3 transmission state, and the reflection phase is 0° at this time; finally, when the level values of C1 and C2 are both low level "00", the transmission state of the SP4T switch (single-pole four-throw switch 14) is RFC-RF4, and the corresponding reflection phase is 90°. In this way, the system can flexibly realize dynamic regulation of the reflection phase to adapt to different application scenarios and requirements.

[0050] like Figure 2 As shown, in one embodiment of the present invention, the dual-polarized antenna unit includes a metal parasitic patch layer 5, a first dielectric substrate 6, a metal radiation patch layer 7, a second dielectric substrate 8 and a metal ground 9 arranged in sequence from top to bottom; wherein, the surface of the metal radiation patch layer 7 integrates a horizontal polarization feeding point 10 and a vertical polarization feeding point 11, and the two feeding points are connected to the bottom microstrip line through a metal via penetrating the second dielectric substrate 8, and then connected to the controller of the polarization beam controller array 2. In specific implementation, the design frequency of the dual-polarized antenna unit is 2.45 GHz, the radiation patch has two feeding points, namely the feeding point 10 for exciting horizontal polarization and the feeding point 11 for vertical polarization, the metal parasitic patch layer 5 is a square patch with a side length of 34.25 mm, the relative dielectric constant and loss angle of the first layer of dielectric substrate 6 are 2.2 and 0.009 respectively, and the dielectric thickness is 6 mm, the metal radiation patch layer 7 is a square patch with a side length of 32.6 mm, the relative dielectric constant and loss angle of the second layer of dielectric substrate 8 are 3 and 0.0013 respectively, and the dielectric thickness is 1.524 mm, and the size of the metal ground 9 is 60 mm*60 mm.

[0051] In one embodiment of the present invention, based on the digital voltage control module 3, the phase state of the metasurface antenna array is dynamically controlled by the following phase compensation formula to achieve precise control of the reflected beam pointing direction: Where k0 is the propagation constant in free space, R mn is the distance from the (m,n)th dual-polarized antenna unit to the feed antenna (4), is the distance from the (m,n)th element to the center of the dual-polarized antenna array (1), is the reflected beam pointing vector of the codeable metasurface antenna array.

[0052] Based on the above technical concept, it should be noted that in order to match the designed 2-bit coding unit, after the phase state of the metasurface antenna array is dynamically controlled, the phase of the metasurface antenna array needs to be fuzzy quantized to minimize the overall phase error of the metasurface antenna array and make the signal of each unit The directional phases are close, achieving effective energy superposition and ultimately forming a beam pointing in that direction.

[0053] It is understandable that a "2-bit coding unit" refers to a unit that uses two binary bits (i.e., 2 bits) to represent a coding state in a codable metasurface antenna array. Each bit can take the value of 0 or 1, so 2 bits can be combined to form 4 different coding states (00, 01, 10, 11), which correspond to different phases or polarization states of the antenna unit. In a codable metasurface antenna array system, each antenna unit can respond to an external control signal, switch its own radiation characteristics and phase state, and thus achieve dynamic control of electromagnetic waves. Specifically for polarization-multiplexed codable metasurface antenna arrays, 2-bit coding units can be used to represent four reflection phase states (for example, 0°, 90°, 180°, 270°), or two polarization states (for example, polarization matching and polarization isolation).

[0054] Therefore, in the above phase compensation formula, in order to match the designed 2-bit coding unit, the calculated continuous phase value needs to be fuzzy quantized so that the phase state of each antenna unit can be represented by a two-bit code while ensuring that the overall phase error is minimized, thereby achieving precise control of the beam pointing.

[0055] As an explanation of the advantages of the present invention in solving the problem of regulating incident signals at any polarization angle and eliminating polarization coverage blind spots to meet the requirements of modern wireless communication systems for high-performance, multi-functional antennas:

[0056] like Figure 6a-6b As shown in the figure, the coding method and two-dimensional far-field radiation pattern of the polarization-multiplexed codeable metasurface antenna array at the 2.45GHz frequency point when the beam direction is (0°, 0°) are demonstrated. It can be clearly seen from the figure that the antenna array proposed in the present invention achieves a maximum gain of up to 22.76dB in the normal direction, and the sidelobe suppression effect is significant, exceeding 12dB, and the overall performance is excellent.

[0057] like Figure 7a-7b As shown in the figure, the coding method and two-dimensional far-field pattern are demonstrated at the same frequency when the beam direction is (60°, 0°), which verifies that the antenna array proposed in the present invention can achieve a beam scanning range of up to 60°, and the beam pointing is precise and the directionality is good.

[0058] In addition, if Figure 4As shown in FIG, the main polarization and cross-polarization simulation radiation patterns of the dual-polarization antenna unit are given, showing that the level suppression of cross-polarization relative to the main polarization reaches about 22.5dB, indicating that the antenna unit has good polarization purity.

[0059] Furthermore, if Figure 5 As shown in the figure, the simulation curve depicts the change of the reflection phase of the dual-polarized antenna unit with frequency in four different phase states. The results show that in the frequency band of 2.35GHz to 2.55GHz, the reflection phase difference can stably change within the range of 90°±20°, ensuring the accuracy and stability of phase control.

[0060] At this point, different from the existing technology, the present invention twists the polarization of the reflected wave through encoding, so that the reflected signal has complete coverage in the polarization space. Regardless of the polarization state of the receiving antenna, the system can achieve good signal coverage quality. This jointly proves the excellent performance of the designed polarization-multiplexed codable metasurface antenna array in terms of gain, sidelobe suppression, beam scanning range and polarization purity, as well as the stable phase control capability within a wide frequency band.

[0061] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A polarization-multiplexed, coded metasurface antenna array, characterized by: include: A dual-polarization antenna array (1) is composed of dual-polarization antenna units arranged in a two-dimensional periodic pattern, each of the dual-polarization antenna units being provided with an independent horizontal polarization feeding point (10) and a vertical polarization feeding point (11) for respectively exciting orthogonal polarization waves; A polarization beam controller array (2) includes controllers corresponding to the number of dual-polarization antenna units, two radio frequency channels of each controller are connected to the feed point of the corresponding dual-polarization antenna unit through metal vias, and each controller includes an inverter (12), a plurality of single-pole double-throw switches (13), a plurality of single-pole four-throw switches (14) and a bridge (15); A feed antenna (4) is located directly in front of the geometric center of the dual-polarized antenna array (1); The digital voltage control module (3) is connected to the polarization beam controller array (2) through an inner layer line, and synchronously drives the single-pole four-throw switch (14) through the C1 and / or C2 control lines to generate a reflection phase state of 0°, 90°, 180°, or 270°, so as to realize dynamic regulation of the polarization mode and phase state of the dual-polarization antenna unit, wherein: The input and output ends of the inverter (12) are respectively connected to the control pin V1 of the single-pole double-throw switch (13) to simplify circuit control; The digital voltage control module (3) realizes the switching of the polarization matching state and / or polarization isolation state of the metasurface antenna array and the feed antenna (4) by controlling the input level of the inverter (12), and the process is as follows: When the inverter input is low, the H / V polarized signals of the dual-polarized antenna array are directly transmitted to the single-pole four-throw switch through their respective channels. After phase adjustment, they are reflected back to the original feeding point, achieving polarization matching between the metasurface antenna array and the feed antenna. When the inverter input is high, the H / V polarized signal is coupled through a bridge and then phase-modulated through a single-pole four-throw switch, and finally cross-transmitted to the other party's feeding point, realizing polarization isolation between the metasurface antenna array and the feed antenna.

2. The polarization-multiplexed, codeable metasurface antenna array according to claim 1, wherein: Each of the controllers includes an inverter (12), two single-pole double-throw switches (13), four single-pole four-throw switches (14) and a bridge (15), wherein: Each of the single-pole double-throw switches (13) is provided with an RFC input channel and two output channels, RF1 and RF2. The RFC input channel of the first single-pole double-throw switch is connected to the horizontal polarization feed point (10), the RF1 output channel is connected to the first single-pole four-throw switch, and the RF2 output channel is connected to the input end of the bridge (15); the RFC input channel of the second single-pole double-throw switch is connected to the vertical polarization feed point (11), the RF1 output channel is connected to the output end of the bridge (15), and the RF2 output channel is connected to the second single-pole four-throw switch (14), thereby achieving output channel switching by controlling the level of the pin V1; The single-pole four-throw switch (14) is provided with an RFC input channel and four output channels RF1, RF2, RF3 and RF4 respectively connected to four sections of terminal transmission lines. The connection length of the RF1 output channel is The RF2 output channel is connected to an open line with a length of a, and the RF3 output channel is connected to an open line with a length of The RF4 channel is connected to a short-circuit with a length of a. By controlling the high and low levels of C1 and / or C2, the connectivity between the RFC input channel and the four output channels is switched, thereby generating four reflection phase states. Where λ is the operating wavelength.

3. The polarization-multiplexed, codeable metasurface antenna array according to claim 1 or 2, wherein: The single-pole four-throw switch (14) generates four reflection phase states by controlling the levels of C1 and C2, and the corresponding control relationship for realizing dynamic regulation is as follows: when C1=1 and C2=0, the generated reflection phase is 180°; when C1=0 and C2=1, the generated reflection phase is 270°; when C1=1 and C2=1, the generated reflection phase is 0°; when C1=0 and C2=0, the generated reflection phase is 90°, wherein 0 and 1 represent low level and high level, respectively.

4. The polarization-multiplexed, codeable metasurface antenna array according to claim 1, wherein: The dual-polarized antenna unit comprises a metal parasitic patch layer (5), a first dielectric substrate (6), a metal radiation patch layer (7), a second dielectric substrate (8) and a metal ground (9) arranged in sequence from top to bottom; wherein a horizontal polarization feeding point (10) and a vertical polarization feeding point (11) are integrated on the surface of the metal radiation patch layer (7), and the two feeding points are connected to the bottom microstrip line through metal vias penetrating the second dielectric substrate (8), and further connected to the controller of the polarization beam controller array (2).

5. The polarization-multiplexed, codeable metasurface antenna array according to claim 4, wherein: The frequency of the dual-polarized antenna unit is 2.45 GHz. The metal parasitic patch layer (5) uses a square patch with a side length of 34.25 mm. The relative dielectric constant and loss angle of the first dielectric substrate (6) are 2.2 and 0.009 respectively, and the dielectric thickness is 6 mm. The metal radiation patch layer (7) uses a square patch with a side length of 32.6 mm. The relative dielectric constant and loss angle of the second dielectric substrate (8) are 3 and 0.0013 respectively, and the dielectric thickness is 1.524 mm. The size of the metal ground (9) is 60 mm*60 mm.

6. The polarization-multiplexed, codeable metasurface antenna array according to claim 3, wherein: The digital voltage control module (3) is based on a field programmable gate array hardware system and controls the level states of the pins V1, C1 and C2 through preset coding logic, thereby realizing dynamic regulation of the polarization mode and phase state of the dual-polarization antenna unit.

7. The polarization-multiplexed, codeable metasurface antenna array according to claim 6, wherein: Based on the digital voltage control module (3), the phase state of the metasurface antenna array is dynamically controlled by the following phase compensation formula to achieve precise control of the reflected beam pointing: Where k0 is the propagation constant in free space, R mn is the distance from the (m,n)th dual-polarized antenna unit to the feed antenna (4), is the distance from the (m,n)th element to the center of the dual-polarized antenna array (1), is the reflected beam pointing vector of the codeable metasurface antenna array.

8. The polarization-multiplexed, codeable metasurface antenna array according to claim 7, wherein: The total size of the metasurface antenna array is 960 mm*960 mm, and the feed antenna (4) is located 250 mm in front of the geometric center of the dual-polarized antenna array (1), so as to ensure that the feed antenna can uniformly excite the array units within the effective working range of the metasurface antenna array, thereby achieving efficient radiation and reception of electromagnetic waves.

9. The polarization-multiplexed, codeable metasurface antenna array according to claim 7, wherein: After dynamically regulating the phase state of the metasurface antenna array, it is also necessary to fuzzy quantize the phase of the metasurface antenna array so that the overall phase error of the metasurface antenna array is minimized and the signal of each unit is The directional phases are close, achieving effective energy superposition and ultimately forming a beam pointing in that direction.

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