Active transmission type intelligent metasurface and matched circuit applied to intelligent metasurface

Abstract

The invention discloses an active transmission type intelligent metasurface and a matched circuit applied to the intelligent metasurface, and the circuit comprises a receiving antenna which is used for receiving an incident electromagnetic wave signal; the power amplification unit is used for amplifying the electromagnetic wave signal received by the receiving antenna; the phase coupling unit is used for modulating the amplified electromagnetic wave signal into various electromagnetic wave signals with different phase differences; the phase selection unit is used for selecting the electromagnetic wave signal with the required phase difference from the electromagnetic wave signals with different phase differences; the radiating antenna is used for radiating an electromagnetic wave signal corresponding to the phase difference; the intelligent metasurface comprises a plurality of active transmission intelligent metasurface units which are periodically arranged to form an N * M array, and each active transmission intelligent metasurface unit in the array comprises an active transmission circuit. According to the invention, an active amplification function which is not possessed by an existing transmission RIS structure is realized, a 2-bit phase regulation function is possessed, the design complexity is relatively low, the deployment cost is relatively low, and the system performance is relatively good.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to an active transmission type intelligent metasurface and a matching circuit applied to the intelligent metasurface. Background Art

[0002] In the development of 6G communication technology, active and passive reconfigurable intelligent metasurfaces (RIS) play a vital role. They optimize network performance by controlling the propagation path of wireless signals. Passive RIS relies on its large number of passive reflective elements to change the phase of the incident signal. It does not require external power supply and consumes almost no power. However, passive RIS has a major limitation, namely the "multiplicative fading" effect. This physical phenomenon causes the signal reflected by RIS to suffer huge path loss during propagation. Especially in the scenario of strong direct channel, this effect will significantly limit the improvement of system capacity. Multiplicative fading is an important concept in the field of wireless communication, especially when it comes to the application of reconfigurable intelligent metasurface (RIS) technology. This phenomenon usually occurs when reflective elements are used to enhance or modify the wireless signal path. In wireless communication, the propagation of signals from the transmitter to the receiver will experience various forms of attenuation or fading. Fading can be divided into additive fading and multiplicative fading. Additive fading is mainly caused by environmental noise or interference, which affects the signal in an additive form during signal transmission. In contrast, multiplicative fading is caused by the characteristics of the propagation medium, especially when the signal undergoes multiple reflection or transmission processes, each process may introduce a certain amount of attenuation, and these attenuation factors are multiplied, ultimately significantly affecting the strength of the received signal.

[0003] Multiplicative fading is particularly noticeable for systems that use passive RIS, which is typically composed of multiple passive components that reflect the incoming signal in the direction of the desired signal. During this process, the signal first travels from the transmitter to the RIS and then reflects from the RIS to the receiver. The attenuation along each path affects the signal, and these factors are mathematically multiplied, hence the name multiplicative fading. Specifically, if the signal experiences a certain amount of attenuation on the path from the transmitter to the RIS, and then again on the path from the RIS to the receiver, the total attenuation effect is the product of these two attenuation factors. The effects of multiplicative fading generally make passive RIS ineffective in environments with strong direct links (direct communication paths between transmitters and receivers), because even if the RIS can provide some path gain, the large amount of attenuation caused by multiplicative fading still limits the improvement in system performance. This is why RIS technology is particularly effective in scenarios where the direct link is blocked or very weak, because in these cases, the gain provided by the RIS can significantly improve the communication quality, and this effect significantly increases the overall path loss, limiting the applicability of RIS in various communication scenarios. In addition, communication transmission through a transmissive RIS may introduce non-negligible insertion losses, which can be as high as 5.7 dB or more in some cases. Phase shift losses caused by electronic components also significantly limit the propagation distance of RIS-assisted systems. Compared with 1-bit RIS systems, 2-bit designs show better performance in sidelobe level control while maintaining low complexity. After recognizing these shortcomings, active RIS with signal amplification capabilities has become a new research topic for improving signal quality. Summary of the invention

[0004] In view of the technical defects and disadvantages existing in the prior art, the embodiments of the present invention provide a smart metasurface and an active transmission circuit applied to the smart metasurface to overcome the above problems or at least partially solve the above problems. The specific scheme is as follows:

[0005] As a first aspect of the present invention, a supporting circuit for a smart metasurface is provided, the circuit comprising: a receiving antenna, a power amplification unit, a phase coupling unit, a phase selection unit and a radiating antenna;

[0006] The receiving antenna is used to receive incident electromagnetic wave signals;

[0007] The power amplification unit is used to amplify the electromagnetic wave signal received by the receiving antenna;

[0008] The phase coupling unit is used to modulate the amplified electromagnetic wave signal into electromagnetic wave signals with various phase differences;

[0009] The phase selection unit is used to select an electromagnetic wave signal with a desired phase difference from electromagnetic wave signals with various phase differences;

[0010] The radiating antenna is used to radiate the electromagnetic wave signal selected by the phase selection unit.

[0011] Furthermore, the power amplifier unit includes a power amplifier chip and a power amplifier power supply circuit, the power amplifier power supply circuit is used to supply power to the power amplifier chip, and the power amplifier chip is used to amplify the electromagnetic wave signal received by the receiving antenna.

[0012] Furthermore, the phase selection unit includes a multi-way selection switch and a phase shift control circuit, the multi-way selection switch includes multiple control signal terminals, the phase shift control circuit is used to input a high level or a low level signal to each control signal terminal respectively, and the multi-way selection switch determines the switch to be turned on by detecting the level signal combination of each control signal terminal.

[0013] Furthermore, the phase coupling unit is a four-phase coupler, which is used to modulate the amplified electromagnetic wave signal into four electromagnetic wave signal outputs with different phase differences of 0°, 90°, 180° and 270°, and the phase selection unit is used to select an electromagnetic wave signal with a desired phase difference from the four electromagnetic wave signals with different phase differences of 0°, 90°, 180° and 270°.

[0014] Furthermore, the phase selection unit includes a four-way selection switch and a phase shift control circuit, the four-way selection switch includes four independent switches, the four electromagnetic wave signals with different phase differences are respectively connected to the radiating antenna through the four independent switches, and the phase shift control circuit is used to control one of the four independent switches to be closed so that the electromagnetic wave signal with the corresponding phase difference is radiated through the radiating antenna.

[0015] Furthermore, the four-way selection switch is a four-way selection switch of model MXD8641H, and the four-way selection switch includes two control signal terminals, namely a first control signal terminal and a second control signal terminal. The phase shift control circuit is used to input a high level or a low level signal to the first control signal terminal and the second control signal terminal. The four-way selection switch determines the switch that is turned on by detecting the level signal combination of the two control signal terminals.

[0016] Furthermore, the first switch of the four-way selection switch is used to output an electromagnetic wave signal with a phase difference of 0°, the second switch is used to output an electromagnetic wave signal with a phase difference of 90°, the third switch is used to output an electromagnetic wave signal with a phase difference of 180°, and the fourth switch is used to output an electromagnetic wave signal with a phase difference of 270°;

[0017] The four-way selection switch determines the switch to be turned on by detecting the level signal combination of the two control signal terminals:

[0018] When the level signals of the first control signal terminal and the second control signal terminal are both at high level, turning on the first switch;

[0019] When the level signal of the first control signal terminal is at a low level and the level signal of the second control signal terminal is at a high level, turning on the second switch;

[0020] When the level signals of the first control signal terminal and the second control signal terminal are both at low level, the third switch is turned on;

[0021] When the level signal of the first control signal terminal is at a high level and the level signal of the second control signal terminal is at a low level, the fourth switch is turned on.

[0022] As a second aspect of the present invention, an active transmission type intelligent metasurface is provided, wherein the active transmission type intelligent metasurface comprises a plurality of active transmission intelligent metasurface units, wherein the plurality of active transmission intelligent metasurface units are periodically arranged to form an N*M array, wherein each of the active transmission intelligent metasurface units in the array comprises an active transmission circuit applied to an intelligent metasurface as described above; the receiving antenna is arranged on the upper surface of the active transmission intelligent metasurface unit, and the radiating antenna is arranged on the lower surface of the active transmission intelligent metasurface unit.

[0023] Furthermore, the receiving antenna and the radiating antenna are both metal patch antennas, and the receiving antenna and the radiating antenna respectively form an N*M metal patch antenna array corresponding to the active transmission smart metasurface unit array on the upper and lower surfaces of the smart metasurface.

[0024] Furthermore, the active transmission intelligent metasurface unit is designed as a multi-layer structure, comprising from top to bottom:

[0025] The first component layout layer is used to layout the receiving antenna and the power amplification unit;

[0026] A first dielectric layer, including a first dielectric plate;

[0027] Metallic formations;

[0028] A second dielectric layer, comprising a second dielectric plate;

[0029] The second component layout layer is used to layout the phase coupling unit, the phase selection unit and the radiating antenna.

[0030] Furthermore, the receiving antenna, the power amplification unit, the phase coupling unit, the phase selection unit and the radiating antenna are connected in sequence through microstrip connecting lines, and each layer of the active transmission intelligent metasurface unit is provided with a via hole for the microstrip connecting line to pass through, and the microstrip connecting line at the output end of the power amplification unit of the first layer is connected to the input end of the phase coupling unit of the ninth layer through the via hole.

[0031] The present invention has the following beneficial effects:

[0032] In order to solve the high insertion loss and "multiplicative fading" effect caused by the transmissive RIS in the prior art, the present invention proposes an intelligent metasurface and an active transmissive circuit design applied to the intelligent metasurface, which realizes a 2-bit phase shift function through a four-phase coupler and a four-way selection switch, and integrates a power amplifier chip to realize the active amplification function that the existing transmissive RIS structure does not have, thereby further improving the communication quality of the wireless communication system assisted by the transmissive intelligent metasurface, and the present invention has lower design complexity, lower deployment cost and better system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An active transmission circuit applied to a smart metasurface provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of a control signal setting of a selection switch provided in an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the upper surface of an active transmissive intelligent metasurface unit provided in an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the bottom surface of an active transmissive intelligent metasurface unit provided in an embodiment of the present invention;

[0037] Figure 5 Active transmission intelligent metasurface unit structure parameters provided by the embodiment of the present invention

[0038] Figure 6 A schematic diagram of the stacking of active transmissive smart metasurface units provided in an embodiment of the present invention;

[0039] Figure 7 A diagram showing simulation results of an active transmission intelligent metasurface provided by an embodiment of the present invention;

[0040] Figure 8 A schematic diagram of an active transmission intelligent metasurface phase-shift amplifier circuit evaluation board provided by an embodiment of the present invention;

[0041] Fig. 9A schematic diagram of phase test of an active transmission intelligent metasurface phase-shift amplifier circuit evaluation board provided by an embodiment of the present invention;

[0042] Fig.10 A schematic diagram of return loss and isolation test of an active transmission intelligent metasurface phase-shift amplifier circuit evaluation board provided in an embodiment of the present invention;

[0043] Fig.11 A schematic diagram showing the phase change measurement of the active transmission intelligent metasurface phase-shift amplifier circuit under different power amplifier supply currents provided by an embodiment of the present invention;

[0044] Fig.12 A top view of an active transmissive smart metasurface array provided by an embodiment of the present invention;

[0045] Fig.13 A bottom view of an active transmissive smart metasurface array provided in an embodiment of the present invention;

[0046] Fig.14 A schematic diagram of a phase control test of an active transmission intelligent metasurface array provided in an embodiment of the present invention;

[0047] Fig.15 A schematic diagram of an amplitude control test of an active transmission intelligent metasurface array provided in an embodiment of the present invention;

[0048] Fig.16 A schematic diagram of the active transmission smart metasurface array beamforming test provided by an embodiment of the present invention;

[0049] Fig.17 A schematic diagram for comparing an embodiment of the present invention with an existing design. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described target changes, the relative positional relationship may also change accordingly.

[0052] In each of the accompanying drawings, identical elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not all drawn to scale. In addition, some well-known parts may not be shown in the drawings.

[0053] Many specific details of the present disclosure are described below to provide a clearer understanding of the present disclosure. However, as those skilled in the art will appreciate, the present disclosure may be implemented without following these specific details.

[0054] Figure 1 A supporting circuit for a smart metasurface provided by an embodiment of the present invention, such as Figure 1 As shown, it mainly includes: a receiving antenna, a power amplification unit, a phase coupling unit, a phase selection unit and a radiating antenna, wherein the phase coupling unit and the phase selection unit together constitute a phase shifting circuit;

[0055] The receiving antenna is used to receive incident electromagnetic wave signals;

[0056] The power amplification unit is used to amplify the electromagnetic wave signal received by the receiving antenna;

[0057] The phase coupling unit is used to modulate the amplified electromagnetic wave signal into electromagnetic wave signals with various phase differences;

[0058] The phase selection unit is used to select an electromagnetic wave signal with a desired phase difference from electromagnetic wave signals with various phase differences;

[0059] The radiating antenna is used to radiate the electromagnetic wave signal selected by the phase selection unit.

[0060] In order to solve the high insertion loss and "multiplicative fading" effect caused by the transmissive RIS in the prior art, the present invention proposes a supporting circuit design applied to an intelligent metasurface. By integrating a phase coupling unit and a phase selection unit, various phase shift functions can be realized. By integrating a power amplifier chip, an active amplification function that is not available in the existing transmissive RIS structure can be realized, thereby improving the communication quality of the wireless communication system assisted by the transmissive intelligent metasurface. The present invention has lower design complexity, lower deployment cost and better system performance.

[0061] In some embodiments, the power amplification unit includes a power amplification chip and a power amplifier power supply circuit, the power amplifier power supply circuit is used to power the power amplification chip, and the power amplification chip is used to amplify the electromagnetic wave signal received by the receiving antenna. Optionally, the power amplification unit adopts SKYWorks' SKY65017-70LF power amplifier, and the maximum supply current of the power amplifier is 120mA and the maximum voltage is 5.5V.

[0062] refer to Figure 1 The power amplifier power supply circuit includes inductor PA_L1, inductor PA_L2, inductor PA_L3 and capacitor PA_C4. The power supply Pa_Vdd is connected to the output end of the power amplifier chip through inductors PA_L3, PA_L2 and PA_L1 in sequence to power the power amplifier chip. The power supply Pa_Vdd is also grounded through capacitor PA_C4 to filter the AC component in the power supply.

[0063] In some embodiments, the phase coupling unit is a four-phase coupler, which is used to modulate the amplified electromagnetic wave signal into four electromagnetic wave signal outputs with different phase differences of 0°, 90°, 180° and 270°, and the phase selection unit is used to select an electromagnetic wave signal with a required phase difference from the four electromagnetic wave signals with different phase differences of 0°, 90°, 180° and 270° and transmit it to the radiating antenna.

[0064] In the above embodiment, the four-phase coupler adopts a four-phase coupler of model QF2500Q06, the input end of which receives the amplified electromagnetic wave signal, and independently generates four signals with different phase differences of 0°, 90°, 180° and 270° based on the amplified electromagnetic wave signal, and outputs them through four output channels respectively.

[0065] In some embodiments, the phase selection unit includes a four-way selection switch and a phase shift control circuit, the four-way selection switch includes four independent switches, the four electromagnetic wave signals with different phase differences are respectively connected to the radiating antenna through the four independent switches, and the phase shift control circuit is used to control one of the four independent switches to be closed so that the electromagnetic wave signal with the corresponding phase difference is radiated through the radiating antenna.

[0066] Optionally, the four-way selection switch is a four-way selection switch of model MXD8641H, also known as an SP4T switch. The four-way selection switch includes two control signal terminals, namely a first control signal terminal and a second control signal terminal. The phase shift control circuit is used to input a high level or a low level signal to the first control signal terminal and the second control signal terminal. The four-way selection switch determines the switch that is turned on by detecting the level signal combination of the two control signal terminals.

[0067] Specifically, the first switch of the four-way selection switch is used to output an electromagnetic wave signal with a phase difference of 0°, the second switch is used to output an electromagnetic wave signal with a phase difference of 90°, the third switch is used to output an electromagnetic wave signal with a phase difference of 180°, and the fourth switch is used to output an electromagnetic wave signal with a phase difference of 270°;

[0068] The four-way selection switch determines the switch to be turned on by detecting the level signal combination of the two control signal terminals:

[0069] When the level signals of the first control signal terminal and the second control signal terminal are both at high level, turning on the first switch;

[0070] When the level signal of the first control signal terminal is at a low level and the level signal of the second control signal terminal is at a high level, turning on the second switch;

[0071] When the level signals of the first control signal terminal and the second control signal terminal are both at low level, the third switch is turned on;

[0072] When the level signal of the first control signal terminal is at a high level and the level signal of the second control signal terminal is at a low level, the fourth switch is turned on.

[0073] refer to Figure 1As shown, the phase shift control circuit includes four input signals, namely Switch_Vdd, Vcc1, Vcc2 and Vcc3, wherein the Switch_Vdd is a power supply signal, the Vcc1 is a normal signal, which is set to a low level for a long time, and the phase shift control circuit inputs a high level or a low level signal to the first control signal terminal and the second control signal terminal through Vcc2 and Vcc3. For example, when Vcc2 is at a high level, the corresponding first control signal terminal is a high level signal, and when Vcc3 is at a high level, the corresponding second control signal terminal is a high level signal.

[0074] In some embodiments, the high level is a 3V level signal, defined as 1, and the low level is a 0.3V level signal, defined as 0. By setting the control signal terminal to a high level or a low level, phase adjustment is achieved while maintaining a constant control current of 0.5 μA. By changing the high and low levels of Vcc1, Vcc2 and Vcc3, different phase signal outputs are achieved. The specific settings are as follows: Figure 2 As shown, when Vcc1, Vcc2 and Vcc3 are 011, the output phase is 0°, when Vcc1, Vcc2 and Vcc3 are 001, the output phase is 90°, when Vcc1, Vcc2 and Vcc3 are 000, the output phase is 180°, and when Vcc1, Vcc2 and Vcc3 are 010, the output signal phase is 270°.

[0075] In the above embodiment, Vcc1 is constantly set to 0, that is, a low level. Therefore, only the levels of Vcc2 and Vcc3 actually change. By combining the level changes of Vcc2 and Vcc3, signal outputs with four phase differences are achieved, thereby realizing a 2-bit phase shift function.

[0076] As another embodiment of the present invention, an active transmission type intelligent metasurface is also provided, wherein the active transmission type intelligent metasurface comprises a plurality of active transmission intelligent metasurface units, wherein the plurality of active transmission intelligent metasurface units are periodically arranged to form an N*M array, and each of the active transmission intelligent metasurface units in the array comprises an active transmission circuit applied to the intelligent metasurface as described in any one of the above descriptions; the receiving antenna is arranged on the upper surface of the active transmission intelligent metasurface unit (the upper surface can also be described as the front surface or the signal receiving surface), and the radiating antenna is arranged on the lower surface of the active transmission intelligent metasurface unit (the lower surface can also be described as the back surface, the signal radiation surface or the signal transmission surface).

[0077] Among them, the receiving antenna and the radiating antenna are both metal patch antennas, and the receiving antenna and the radiating antenna respectively form an N*M metal patch antenna array corresponding to the active transmission smart metasurface unit array on the upper surface and the lower surface of the smart metasurface.

[0078] Figure 3-4 Schematic diagram of the upper and lower surfaces of the active transmission intelligent metasurface unit provided in an embodiment of the present invention, refer to Figure 3 As shown, the upper surface of the active transmission intelligent metasurface unit is provided with a receiving patch (i.e., a metal patch antenna as a receiving antenna) and a power amplification unit, referring to Figure 4 The lower surface of the active transmission intelligent metasurface unit is provided with a phase coupling unit, a phase selection unit and a radiation patch (i.e., a metal patch antenna serving as a radiation antenna). The receiving antenna, the power amplification unit, the phase coupling unit, the phase selection unit and the radiation antenna are electrically connected in sequence through microstrip connecting lines, and the microstrip connecting lines pass from the upper surface to the lower surface through vias, wherein the four-phase coupler and the four-way selection switch are connected by four microstrip lines of equal length.

[0079] The structural parameters of the active transmission intelligent metasurface unit are as follows: Figure 5 shown.

[0080] like Figure 6 As shown, in some embodiments, the present invention further provides a nine-layer stacked structure, the nine-layer stacked structure comprising from top to bottom:

[0081] The first layer is a first element layout layer, which is used to layout receiving antennas and power amplifier units, including N*M metal patch antenna arrays as receiving antennas, and the same number of power amplifier units corresponding to the metal patch antennas one by one;

[0082] The second layer is a first semi-cured layer, including a first semi-cured sheet, which is used for laminating different layers of the circuit board, and has a thickness of 0.2108 mm. The first layer structure and the third layer structure are respectively located on the upper surface and the lower surface of the first layer of semi-cured sheet;

[0083] The third layer is the first dielectric layer, including the first dielectric plate, the material of which is epoxy glass cloth laminate (FR-4) with a thickness of 0.6 mm;

[0084] The fourth layer is the upper metal stratum, including the upper metal floor;

[0085] The fifth layer is a second semi-cured layer, including a second semi-cured sheet, which is used for bonding the upper and lower metal floors, and has a thickness of 0.2028 mm. The upper surface and the lower surface of the second semi-cured sheet are the upper and lower metal floors respectively;

[0086] The sixth layer is the lower metal stratum, including the lower metal floor;

[0087] The seventh layer is the second dielectric layer, which includes a second dielectric board, and its material is epoxy glass cloth laminate (FR-4) with a thickness of 0.6 mm;

[0088] The eighth layer is a third semi-cured layer, including a third layer of semi-cured sheet, which is used for laminating different layers of the circuit board, and has a thickness of 0.2108 mm. The seventh layer structure and the ninth layer structure are respectively located on the upper surface and the lower surface of the third layer of semi-cured sheet;

[0089] The ninth layer is the second element layout layer: it is used to layout phase coupling units, phase selection units and radiating antennas, including N*M metal patch antenna arrays as radiating antennas, and the same number of phase coupling units, phase selection units and radiating antennas corresponding one by one to the metal patch antennas.

[0090] It should be noted that the stacked structure may also exist in other hierarchical forms and is not limited to those provided in the embodiments of the present invention. The stacked structure provided in the embodiments is mainly used to carry the active transmission type intelligent metasurface unit described in the present invention. The creativity of the present invention lies in the active transmission type intelligent metasurface unit. Any stacked structure that can be equipped with the active transmission type intelligent metasurface unit described in the present invention is within the protection scope of the present invention.

[0091] The following are the simulation results of the present invention:

[0092] The simulation was performed using the electromagnetic simulation software Ansys Electronics Desktop 2021R2.

[0093] The upper excitation surface is set as Flopuet port: 1 to simulate the incident wave excitation; the lower excitation surface is set as Flopuet port: 2 to receive the transmitted electromagnetic wave; the unit is set as periodic boundary conditions around it to simulate the infinite active transmission smart metasurface array structure, the simulation center frequency: f = 2.6GHz active transmission smart metasurface simulation results are shown in Figure 7 As shown, the return loss of the incident wave is within the band (frequency range of 2.57 GHz to 2.62 GHz), and the active transmission RIS always keeps the return loss below -4 dB, and the insertion loss is kept below -12 dB in this frequency range.

[0094] The following are the test results of the present invention, which mainly include the following tests:

[0095] Phase shift amplifier circuit test:

[0096] In order to verify the reliability of the cascade connection between the components selected above, the present invention designs an evaluation circuit, such as Figure 8As shown. The input RF signal is output after passing through the power amplifier, four-phase coupler and SP4T switch in sequence. According to the official technical manual, the SKY65017-70LF power amplifier provides 20dB signal enhancement, which effectively compensates for the attenuation caused by the introduction of RIS in the transmission system and the electronic components used in the design. The maximum supply current of the power amplifier is 120mA and the maximum voltage is 5.5V. Under actual conditions, the maximum gain provided by the power amplifier is 16dB. The positive power supply voltage Vcc is connected to pin 3 of the amplifier through a decoupling network composed of PA_C4, PA_L1, PA_L2 and PA_L3.

[0097] Using the phase control method based on the SP4T switch control signal, the output state of the SP4T switch is determined by three control signals (Vcc1, Vcc2 and Vcc3). By setting the control signal to a high level (3V, defined as 1) or a low level (0.3V, defined as 0), the phase adjustment is achieved while maintaining a constant control current of 0.5μA. The phase adjustment is not directly related to the control current, but is determined by the high and low states of the control signal level, thereby achieving independent control of the phase and current. In the experiment, the control signal is initially set to 011, defined as the reference state, corresponding to the 0° phase of the output signal of the phase shift circuit, as shown in Figure 2 As shown in , this setting provides a reference for subsequent phase comparison. Subsequently, the control signal is adjusted to 001, and it is observed that the phase difference of the output signal is close to 90° relative to the reference state, as shown in Fig. 9 As shown. This result shows that the phase shift circuit effectively achieves a quarter-cycle phase shift under this control signal. Further, in order to fully evaluate the performance of the phase shift circuit, the control signal was changed to 000 and 010 respectively. The measurement results under these settings show that within the frequency band of interest, the phase difference of the output signal relative to the reference phase is stable at around 180° and 270° respectively. This observation confirms the stability and reliability of the phase shift circuit under different control signals and demonstrates its accuracy in achieving the predetermined phase change. The measurement results of the evaluation board also show that the phase shift amplifier circuit is Fig.10 The output phase curve of the evaluation board is obtained by adjusting the power supply current of the power amplifier at 2.6GHz. Fig.11 As shown in Figure 2, the amplification and phase shifting circuits maintain good phase consistency at different active gain levels, with a phase error of less than 8°.

[0098] Active Transmissive Smart Metasurface Array Test Environment:

[0099] The design of active transmission RIS array is as follows: Fig.12 and Fig.13As shown. The overall structure of the array is a 310×310 mm FR-4 printed circuit board, which adopts a laminated board structure consistent with the unit design. The structure is bonded together by two layers of 0.8 mm thick FR-4 substrate through a lamination process. The array is divided into two parts, the upper and lower parts, with a total of 16 independent active transmission-type RIS units. Each unit is equipped with an independent control circuit, including a phase shift control circuit and a power amplifier power supply circuit. These circuits are connected to the two sockets on the top of the array and communicate with the control board at the rear through cables. This design allows the active gain and phase of each unit to be independently adjusted throughout the active transmission-type RIS array;

[0100] The phase control capability and signal amplification efficiency of the proposed active transmission RIS array were tested. The experiment was conducted in a microwave darkroom. The test setup included two standard gain horn antennas, used as transmitter and receiver respectively. An 8×4 active transmission RIS array with 32 elements was placed on the central turntable in the darkroom, allowing multi-angle and directivity measurements. The transmitting horn antenna was placed vertically at the center of the receiving surface of the active transmission RIS array, keeping a distance of 60 cm to ensure vertical incidence and good beam coverage. The receiving horn antenna was in the same horizontal plane as the active transmission RIS array and the receiver, and was perpendicular to the radiation surface of the RIS array. The distance between the receiver and the active transmission RIS array was 4 meters. This designed test setup enables us to comprehensively and accurately evaluate the performance of the active transmission RIS array, especially the key technical indicators such as phase control and signal amplification, in a controlled and standardized environment.

[0101] In the test of active transmissive smart metasurface array, a fast beamforming algorithm with low training / feedback overhead was applied. As a blind beamforming technique, this algorithm does not require additional channel information or user location data, but only adjusts the phase configuration based on the feedback of signal quality provided by the receiver. It is particularly suitable for complex and dynamic communication environments. The algorithm can quickly respond to environmental changes and adjust its beamforming coefficients accordingly. This algorithm aims to optimize the signal reception quality in wireless communication systems by adjusting the transmission phase of RIS. At the beginning of the process, an M*N complex matrix T0 is initialized to represent the initial state of the RIS transmission coefficient. After this initialization, the algorithm receives the initial feedback of the receiving end (RX) signal power p0 to establish a baseline for subsequent comparison and adjustment. Then, the algorithm is divided into two main steps: horizontal search and vertical search.

[0102] Horizontal search: This step focuses on each column of the RIS matrix. For each column (from column 1 to column N), the algorithm tries to optimize the received signal power by changing the phase of the current column. Specifically, the algorithm increases the phase of the current column by 90° and then receives the signal power feedback p under the new configuration. n, if the new configuration maintains or improves the received power (p n-1 ≥p n ), then keep the change; otherwise, restore to the previous configuration and keep the original configuration.

[0103] Vertical Search: After completing the horizontal search, the algorithm shifts its focus to each row of the RIS matrix. This process is similar to the horizontal search, but operates on rows instead of columns. Again, the algorithm changes the phase of each row to try to find a better transmission coefficient configuration to enhance the received signal power.

[0104] Through these iterative steps, the algorithm gradually optimizes the transmission coefficient configuration of the entire RIS array. Since the algorithm only adjusts one row or one column at a time, it gradually improves the signal-to-noise ratio (SNR) of the system without causing significant fluctuations in the received power. This step-by-step iterative method has very low complexity.

[0105] Active transmission intelligent metasurface array phase amplitude control test:

[0106] The active transmissive RIS array was set to run at full power to ensure accurate evaluation of its capabilities. The control signal of each unit selection switch was switched in sequence to achieve a uniform phase change of the entire array. By switching four different states in the frequency range of 2.55-2.57GHz in sequence, the phase difference of these four specific states was close to 90°. This process verified the accuracy of the fabricated active transmissive RIS in phase control, such as Fig.14 shown.

[0107] In order to analyze the changes in the RIS radiation pattern under different active gain levels, the receiving angle of the receiver is adjusted to 0°, and then the array transmission beam is directed to the receiver through the beamforming algorithm mentioned above. By controlling the input power, the response characteristics of the received signal at each power level are recorded. Subsequently, the RIS array pattern under each power state is measured, such as Fig.15 As shown in the figure, the measurement results show that the active transmission RIS array has good active gain control capability. When the power amplifier chip's supply current is 2.6A, the power at the receiver reaches a peak value. Compared with the lowest supply current of 0.01A, this peak value represents a significant increase of 11.9dB in received power. At the same time, the active transmission RIS array exhibits a gradually adjustable radiation power characteristic during the entire power regulation process. This characteristic is crucial for achieving amplitude regulation of each array unit. This finding also proves the ability of the active transmission RIS to amplify the incident signal, which is not available in traditional RIS systems. Fig.16As shown, when the power amplifier is operated at high current, providing significant active gain, the radiation pattern exhibits good directivity, and the maximum gain of the main lobe decreases synchronously with the active gain. This ensures signal strength and consistency, maintaining good beam directivity, however, when the operating current is lower, such as 0.2A and 0.01A, the pattern changes significantly because the reduction in active gain weakens the consistency of the beam. Higher active gain helps maintain consistency, effectively focusing energy on the main lobe. Lower gain may cause beam dispersion, change the main lobe shape and relatively increase the sidelobe level. In addition, lower active gain makes the system more susceptible to nonlinear effects, further affecting the beam shape and sidelobe levels.

[0108] Active Transmissive Smart Metasurface Array Beamforming Test:

[0109] During the test, the position of the receiving antenna was first ensured to remain fixed, and then the central turntable in the microwave anechoic chamber was rotated, starting from 0° and increasing in increments of 10° until it reached 60°, covering a total of seven different angles. The purpose was to fully evaluate the beam control performance of the active transmission-type RIS system at various angles. At each specified angle, the optimization algorithm was run once. After the optimization was completed at each angle, the state of the array was not changed, and the radiation pattern was measured in detail using a vector network analyzer. Fig.17 The directional pattern shown demonstrates the beam steering capability of the transmissive RIS system within a ±60° deflection range. The asymmetry in the radiation pattern can be attributed to factors such as the incomplete symmetry of the array element structure, uneven element distribution, mutual coupling, and manufacturing errors. The system performs best at a 0° deflection angle, when the transmissive RIS is directly aimed at the target direction. In this state, it achieves the highest gain and the narrowest main lobe width of 14°. This combination of high gain and narrow main lobe width is an ideal response to the need for precise directional transmission.

[0110] As the deflection angle of the receiver increases, the system performance gradually decreases. When the deflection angle reaches a certain value, such as ±50°, the half-power beamwidth of the radiation pattern remains below 18°, showing good directional control capability, and the gain performance only decreases by about 3.5dB. In addition, at a deflection angle of 60°, the half-power beamwidth increases to 22°. This phenomenon shows that although the transmission-type RIS maintains a certain beam control capability within a wider range, the directional and focusing capabilities are reduced under extreme deflection angle conditions.

[0111] Overall, the measurement results confirm the system's high reliability in precise phase control, signal amplification, adaptability and dynamic communication environments. In addition, the measurement results further emphasize the significant potential of this technology in enhancing the performance of wireless communication systems and coping with the double fading effects of traditional RIS.

[0112] exist Fig.17 The present invention is compared with the existing design in detail. Compared with the existing active RIS design, the design proposed in this paper shows significant advantages in many key aspects, especially in terms of compact size and simplified structure. Specifically, our design achieves a reduction of more than 90% in the longitudinal dimension, which not only makes this design more in line with the requirements of equipment miniaturization, but also greatly reduces the production cost of the RIS array, thereby improving economic efficiency.

[0113] In addition, through in-depth searches of existing literature and databases, it was found that active transmission-type RIS structural designs with active amplification functions are relatively scarce on the market. In view of this, the present invention fills the gap in this field to a large extent and provides an innovative solution. This design provides more diverse options for the deployment of RIS in various application scenarios, greatly expanding the application prospects of RIS technology, and thus has extremely high practical value and market potential.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A supporting circuit for a smart metasurface, characterized in that: The circuit comprises: a receiving antenna, a power amplification unit, a phase coupling unit, a phase selection unit and a radiating antenna; The receiving antenna is used to receive incident electromagnetic wave signals; The power amplification unit is used to amplify the electromagnetic wave signal received by the receiving antenna; The phase coupling unit is used to modulate the amplified electromagnetic wave signal into electromagnetic wave signals with various phase differences; The phase selection unit is used to select an electromagnetic wave signal with a desired phase difference from electromagnetic wave signals with various phase differences; The radiating antenna is used to radiate the electromagnetic wave signal selected by the phase selection unit.

2. The supporting circuit for smart metasurface according to claim 1, characterized in that: The phase selection unit includes a multi-way selection switch and a phase shift control circuit. The multi-way selection switch includes multiple control signal terminals. The phase shift control circuit is used to input a high level or a low level signal to each control signal terminal respectively. The multi-way selection switch determines the switch to be turned on by detecting the level signal combination of each control signal terminal.

3. The supporting circuit for smart metasurface according to claim 1, characterized in that: The phase coupling unit is a four-phase coupler, which is used to modulate the amplified electromagnetic wave signal into four electromagnetic wave signal outputs with different phase differences of 0°, 90°, 180° and 270°, and the phase selection unit is used to select an electromagnetic wave signal with a required phase difference from the four electromagnetic wave signals with different phase differences of 0°, 90°, 180° and 270°.

4. The supporting circuit for smart metasurface according to claim 3, characterized in that: The phase selection unit includes a four-way selection switch and a phase shift control circuit. The four-way selection switch includes four independent switches. The four electromagnetic wave signals with different phase differences are respectively connected to the radiating antenna through the four independent switches. The phase shift control circuit is used to control one of the four independent switches to be closed so that the electromagnetic wave signal with the corresponding phase difference is radiated through the radiating antenna.

5. The supporting circuit for smart metasurface according to claim 4, characterized in that: The four-way selection switch includes two control signal terminals, namely a first control signal terminal and a second control signal terminal. The phase shift control circuit is used to input a high level or a low level signal to the first control signal terminal and the second control signal terminal. The four-way selection switch determines the switch that is turned on by detecting the level signal combination of the two control signal terminals.

6. The supporting circuit for smart metasurface according to claim 5, characterized in that: The first switch of the four-way selection switch is used to output an electromagnetic wave signal with a phase difference of 0°, the second switch is used to output an electromagnetic wave signal with a phase difference of 90°, the third switch is used to output an electromagnetic wave signal with a phase difference of 180°, and the fourth switch is used to output an electromagnetic wave signal with a phase difference of 270°; The four-way selection switch determines the switch to be turned on by detecting the level signal combination of the two control signal terminals: When the level signals of the first control signal terminal and the second control signal terminal are both at high level, turning on the first switch; When the level signal of the first control signal terminal is at a low level and the level signal of the second control signal terminal is at a high level, turning on the second switch; When the level signals of the first control signal terminal and the second control signal terminal are both at low level, the third switch is turned on; When the level signal of the first control signal terminal is at a high level and the level signal of the second control signal terminal is at a low level, the fourth switch is turned on.

7. An active transmission type intelligent metasurface, characterized in that: The active transmission type intelligent metasurface comprises a plurality of active transmission intelligent metasurface units, and the plurality of active transmission intelligent metasurface units are periodically arranged to form an N*M array, and each of the active transmission intelligent metasurface units in the array comprises a matching circuit applied to the intelligent metasurface as described in any of claims 1-6; the receiving antenna is arranged on the upper surface of the active transmission intelligent metasurface unit, and the radiating antenna is arranged on the lower surface of the active transmission intelligent metasurface unit.

8. The active transmission type smart metasurface according to claim 7, characterized in that: The receiving antenna and the radiating antenna are both metal patch antennas, and the receiving antenna and the radiating antenna respectively form an N*M metal patch antenna array corresponding to the active transmission smart metasurface unit array on the upper surface and the lower surface of the smart metasurface.

9. The active transmission type smart metasurface according to claim 7, characterized in that: The active transmission intelligent metasurface unit is a multi-layer structure design, which includes from top to bottom: The first component layout layer is used to layout the receiving antenna and the power amplification unit; A first dielectric layer, including a first dielectric plate; Metallic formations; A second dielectric layer, comprising a second dielectric plate; The second element layout layer is used to layout the phase coupling unit, the phase selection unit and the radiating antenna.

10. The active transmission type smart metasurface according to claim 9, characterized in that: The receiving antenna, the power amplifying unit, the phase coupling unit, the phase selecting unit and the radiating antenna are electrically connected in sequence through microstrip connecting lines. Each layer of the active transmission intelligent metasurface unit is provided with vias for the microstrip connecting lines to pass through. The microstrip connecting line at the output end of the power amplifying unit of the first layer passes through the vias and is connected to the input end of the phase coupling unit of the ninth layer.

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