Dual-frequency phase-reconfigurable active intelligent reflector system with negative feedback adjustment

Abstract

The invention discloses a dual-frequency phase-reconfigurable active intelligent reflecting surface system with negative feedback adjustment. The system comprises an intelligent reflecting surface, a phase shift module, a radio frequency amplification module, a negative feedback module and a rear-end control module, the intelligent reflecting surface receives an electromagnetic signal, the phase of the electromagnetic signal is adjusted through the phase shifting module, the amplitude of the electromagnetic signal is adjusted through the radio frequency amplification module, the electromagnetic signal is transmitted to the intelligent reflecting surface, the intelligent reflecting surface reflects the electromagnetic signal subjected to phase modulation amplification processing to a user side, and the negative feedback module receives a returned electromagnetic signal of the user side; and an estimation error signal is calculated and compared with a target parameter, a negative feedback signal is generated and transmitted to the rear-end control module, and the rear-end control module controls the phase shift module and the radio frequency amplification module to perform phase modulation amplification processing so as to realize directional reflection of the electromagnetic signal. According to the invention, signal enhancement can be realized to cope with relatively large physical path fading, and the signal amplification factor can be automatically adjusted under the condition that the received signal is relatively weak.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent reflector surface wireless communication, and in particular to a dual-frequency phase reconfigurable active intelligent reflector surface system with negative feedback regulation. Background Art

[0002] Reconfigurable Intelligent Surface (RIS), also known as smart metasurface or programmable metasurface, is a cutting-edge technology that optimizes wireless communication environments by dynamically manipulating electromagnetic wave properties (such as phase, amplitude, and polarization). A phase-reconfigurable intelligent reflector system consists of an intelligent reflector and a back-end control circuit module. The RIS is composed of a large number of reconfigurable electromagnetic units. Each unit can be dynamically adjusted through external control (e.g., voltage and current) via back-end circuitry, thereby intelligently reflecting or refracting incident electromagnetic waves. The back-end control circuit module typically uses digital control (e.g., FPGA or microcontroller) to adjust and control the adjustable elements in the RIS electromagnetic units, while balancing low power consumption, miniaturization, and high response speed. This control modifies the state of the electromagnetic units to achieve dynamic control of reflected or refracted electromagnetic waves. However, most traditional phase-reconfigurable intelligent reflector systems are based on passive RIS systems, which directly reflect received signals and fail to account for the potential for weak signal power in application scenarios.

[0003] Reconfigurable passive smart reflectors have been widely used in wireless communications due to their low cost, low energy consumption, and easy deployment. However, in most applications, in addition to insufficient signal coverage, they also face challenges such as weak signal strength and communication links that are insufficient for deployment of passive smart reflector systems. In communication systems, repeaters with amplification and forwarding capabilities are often used to amplify and forward received signals to enhance signal strength and extend coverage. However, the significant increase in RF chain requirements and the resulting hardware complexity required to mitigate the significant signal interference generated by repeaters are unacceptable. Therefore, in future 6G applications, it is desirable for smart reflector systems to be able to amplify received signals and avoid the "multiplicative fading" effect associated with passive RIS in scenarios with strong direct links. Addressing these issues is key to the widespread adoption of reconfigurable smart reflector systems.

[0004] Traditional active smart reflectors typically employ amplified reflector arrays, which reflect amplified scattered fields with polarizations orthogonal to the incident beam. To maintain low mutual coupling between antenna ports, the polarizations of different ports must be orthogonal. One limitation of this approach is that it alters the polarization of the scattered waves. Another limitation is that these amplified reflector arrays mostly employ fixed structures and lack reconfigurable components such as phase shifters, making it impossible to achieve the controllable amplified scattering required for active smart reflectors. Therefore, we chose to further investigate a reconfigurable active smart reflector system based on a structure that combines a cascaded smart reflector with a back-end RF amplifier circuit module.

[0005] Currently, research on active smart reflectors is relatively limited, primarily limited to near-field testing of miniaturized active smart reflector system prototypes or the construction of prototypes for research and analysis using a single frequency channel. In real-world applications, wireless networks often utilize more than one frequency band. When faced with the need to operate across multiple frequency bands, investing in multiple active smart reflector systems can result in significant cost penalties. Furthermore, active smart reflector systems are often used in harsh environments, and ensuring that the transmitted signal maintains the required power level is a key consideration in these applications. Therefore, designing an active smart reflector system that can operate across multiple frequency bands and adaptively adjust the signal amplification factor is crucial for practical applications. Summary of the Invention

[0006] In order to overcome the defects and shortcomings of the existing technology, the present invention provides a dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation. The present invention can actively reflect signals at two frequencies to achieve signal enhancement to cope with large physical path fading, and has a negative feedback regulation function, so that it can autonomously adjust the signal amplification factor when the received signal is weak, thereby completing autonomous regulation.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation, comprising: an intelligent reflector, a phase shift module, a radio frequency amplification module, a negative feedback module and a back-end control module;

[0009] The smart reflective surface is connected to the phase shifting module, the phase shifting module is connected to the radio frequency amplification module, the back-end control module is connected to the phase shifting module and the radio frequency amplification module respectively, the smart reflective surface is connected to the negative feedback module, and the negative feedback module is connected to the back-end control module;

[0010] The intelligent reflective surface receives electromagnetic signals, adjusts the phase of the electromagnetic signals through the phase shifting module, and adjusts the amplitude of the electromagnetic signals through the radio frequency amplification module, and transmits them to the intelligent reflective surface. The intelligent reflective surface reflects the electromagnetic signals after phase modulation and amplification to the user end. The negative feedback module receives the return electromagnetic signals from the user end, calculates and compares the estimated error signals with the target parameters, generates negative feedback signals and transmits them to the back-end control module. The back-end control module controls the phase shifting module and the radio frequency amplification module to perform phase modulation and amplification processing respectively to achieve directional reflection of the electromagnetic signals.

[0011] As a preferred technical solution, the smart reflective surface includes: a reflective unit array, a dielectric layer, a reflective backplane and a connection port;

[0012] The reflective unit array is arranged on the front side of the dielectric layer, and the reflective unit array is composed of a plurality of patch units, and the patch units are used to receive or reflect electromagnetic signals;

[0013] The reflective back plate is arranged on the back side of the dielectric layer, the connection port is arranged on the reflective back plate, and the connection port is connected to the phase shift module.

[0014] As a preferred technical solution, the patch unit is further provided with a connecting through-hole, which passes through to the reflective backplane and matches the connecting port to enable active feeding of the phase shift module and the radio frequency amplification module.

[0015] As a preferred technical solution, the phase shift module includes a sub-frequency module, a radio frequency switch, a first connection port, a second connection port and a DC power supply control port;

[0016] The first connection port is connected to the smart reflective surface and the radio frequency amplification module respectively, and is used to transmit the electromagnetic signal received by the smart reflective surface;

[0017] The first connection port is connected to a radio frequency switch, and the radio frequency switch is respectively connected to sub-frequency modules of different operating frequencies;

[0018] The RF switch is also connected to a DC power supply control port, which is connected to a back-end control module. The back-end control module controls the state switching of the RF switch, accesses a sub-frequency module corresponding to the operating frequency, and realizes phase change of the incident electromagnetic signal.

[0019] The radio frequency switch is connected to the second connection port, and the second connection port is connected to the radio frequency amplification module.

[0020] As a preferred technical solution, the sub-frequency module includes: four RF switches, a first reference path, a second reference path, a first delay path, and a second delay path;

[0021] The first reference path, the second reference path, the first delay path, and the second delay path are composed of microstrip lines of different lengths;

[0022] An RF switch is provided at both ends of the first reference path and the first delay path, respectively; an RF switch is provided at both ends of the second reference path and the second delay path, respectively. By switching the four RF switches, the first reference path and the second reference path, the first delay path and the second delay path are combined to achieve phase delays of different angles.

[0023] As a preferred technical solution, the phase change of the signal propagating in the microstrip line is expressed as:

[0024] Δφ=β·L

[0025]

[0026] Where Δφ represents the phase change, β represents the propagation constant, λ represents the signal wavelength, and L represents the length of the microstrip line.

[0027] When the first delay path 306 is longer than the first reference path 305 When , a phase delay of 45° is achieved;

[0028] When the second delay path 309 is longer than the second reference path 308 When , a phase delay of 90° is achieved;

[0029] By switching four RF switches, the first reference path and the second reference path, and the first delay path and the second delay path are combined to achieve phase changes of 0°, 45°, 90°, and 135°.

[0030] As a preferred technical solution, the radio frequency amplification module includes: an input / output port, a radio frequency transistor, a DC blocker, a bias power supply, a microstrip line, a radio frequency resistor, and a radio frequency bypass capacitor;

[0031] The input / output port is connected to the phase shift module to receive the phase-modulated electromagnetic signal, which is amplified by the radio frequency amplification module and then transmitted back to the smart reflective surface through the same port for reflection;

[0032] The gate of the radio frequency transistor is connected to the input / output port, the source of the radio frequency transistor is grounded through a microstrip line and a parallel circuit, the parallel circuit is composed of a radio frequency resistor and a radio frequency bypass capacitor in parallel, the drain of the radio frequency transistor is connected to a DC blocker, and the DC blocker is connected to a bias power supply;

[0033] The gate of the radio frequency transistor is also connected to a dynamic gain adjustment unit for adjusting the amplification factor of the radio frequency amplification module;

[0034] The drain of the radio frequency transistor is also connected to a frequency domain tuner for adjusting the frequency of the electromagnetic signal amplified by the radio frequency amplification module.

[0035] As a preferred technical solution, the dynamic gain adjustment unit is provided with a first microstrip line, a second microstrip line, a third microstrip line, and a fourth microstrip line having different impedance values;

[0036] The first microstrip line is connected to the second microstrip line, the third microstrip line, and the fourth microstrip line respectively through corresponding Schottky diodes. The back-end control module controls the DC power supply to turn on the Schottky diodes corresponding to each microstrip line, thereby changing the impedance value of the access amplifier circuit so that the RF amplifier module operates at different frequencies.

[0037] The frequency domain tuner is provided with a fifth microstrip line and a sixth microstrip line, which are connected via a Schottky diode. The back-end control module controls a DC power supply to turn on the Schottky diode, thereby changing the impedance value of the microstrip line involved in amplification at different operating frequencies.

[0038] As a preferred technical solution, the negative feedback module includes an information acquisition module, an adaptive algorithm module, an error calculation module, and a control signal generation module;

[0039] The information acquisition module is used to collect the electromagnetic signal returned by the user end, using a dual-band coupler with a switchable bandpass filter group, and an IQ demodulator to extract the electromagnetic signal from the user end and then separate the amplitude and phase information of the signal;

[0040] The error calculation module is used to perform error calculation on the electromagnetic signal returned from the user end, calculate the amplitude error and phase error of the electromagnetic signal respectively, and weight them to obtain a comprehensive error, which is then transmitted to the adaptive algorithm module;

[0041] The adaptive algorithm module is used to set an acceptable error range and output a switching control signal of the amplification state according to the relationship between the comprehensive error and the acceptable error range;

[0042] The control signal generation module is used to convert the switching control signal output by the adaptive algorithm module into a physical control signal, and drive the back-end control module to regulate the radio frequency amplification module.

[0043] As a preferred technical solution, the back-end control module includes: a central processing unit module, and a phase shift state control module, a radio frequency amplification frequency control module, a radio frequency amplification control module, an external control module, a discrete codebook control module and a negative feedback receiving module respectively connected to the central processing unit module;

[0044] The phase shift state control module is used to control the operating frequency of the phase shift module;

[0045] The radio frequency amplification frequency control module is used to control the operating frequency selection of the radio frequency amplification module;

[0046] The radio frequency amplification control module is used to control the amplification state selection of the radio frequency amplification module;

[0047] The external control module is used to provide an interactive interface;

[0048] The discrete codebook control module is used to store the codebook corresponding to the reflection angle of the target, and call the codebook to change the state of the phase shift module and the radio frequency amplification module when the electromagnetic signal is reflected;

[0049] The negative feedback receiving module is used to receive the transmission signal of the negative feedback module to realize the change of the amplification state of the radio frequency amplification module.

[0050] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0051] (1) The negative feedback module of the present invention can receive electromagnetic signals from the user end to calculate the signal error, and control the feedback signal generation and transmission to the back-end control module through an adaptive algorithm, so that the system can perform adaptive adjustment and improve the stability of the system in complex environments.

[0052] (2) The RF amplification module of the present invention integrates two operating frequencies, which minimizes the complexity of the RF amplification module. Switching between different operating frequencies can be achieved only through an RF switch, reducing the system structure size and cost.

[0053] (3) The radio frequency amplification module of the present invention has three amplification modes. The amplification coefficient has a certain adjustable range to achieve different amplification effects on electromagnetic signals; at the same time, it can cooperate with the negative feedback module to maintain the stability of the system in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the overall architecture of the dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation of the present invention;

[0055] Figure 2 Schematic diagram of the structure of the intelligent reflective surface of the present invention;

[0056] Figure 3 Schematic diagram of the structure of the phase shift module of the present invention;

[0057] Figure 4 This is a structural diagram of the radio frequency amplification module of the present invention;

[0058] Figure 5 Schematic diagram of the S(1,1) parameters output by the radio frequency amplification module of the present invention at an operating frequency of 1.8 GHz;

[0059] Figure 6 Schematic diagram of the S(1,1) parameters output by the radio frequency amplification module of the present invention at a working frequency of 2.4 GHz;

[0060] Figure 7 Schematic diagram of the structure of the negative feedback module of the present invention;

[0061] Figure 8 This is a topological diagram of the working mode in which the negative feedback module of the present invention modulates the amplification parameters of the radio frequency amplification module;

[0062] Figure 9 It is a structural diagram of the back-end control module of the present invention.

[0063] Among them, 101-intelligent transmitting surface, 102-phase shifting module, 103-RF amplifying module, 104-negative feedback module, 105-back-end control module, 201-reflection unit array, 202-dielectric layer, 203-reflection backplane, 204-patch unit, 205-connection through hole, 206-connection port, 207-sub-dielectric layer, 301-sub-frequency module, 302-first RF switch, 303-first connection port, 304-DC power supply control port, 305-first reference path, 306-first delay path, 307-second RF switch, 308-second reference path, 309-second delay path, 310-second connection port, 410-single input and output basic amplifier circuit, 402-dynamic gain adjustment unit, 403-RF transistor, 40 4-DC blocker, 405-input / output port, 406-bias power supply, 407-frequency domain tuner, 408-microstrip line, 409-RF resistor, 410-RF bypass capacitor, 4001-first microstrip line, 4002-second microstrip line, 4003-third microstrip line, 4004-fourth microstrip line, 4005-fifth microstrip line, 4006-sixth microstrip line, 701-information acquisition module, 702-adaptive algorithm module, 703-error calculation module, 704-control signal generation module, 901-central processing unit module, 902-phase shift state control module, 903-RF amplification frequency control module, 904-RF amplification factor control module, 905-external control module, 906-discrete codebook control module, 907-negative feedback receiving module. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0065] Example

[0066] like Figure 1 As shown, this embodiment provides a dual-frequency phase reconfigurable active smart reflector system with negative feedback regulation, which includes: a smart reflector 101, a phase shifting module 102, a radio frequency amplification module 103, a negative feedback module 104, and a back-end control module 105. The back-end control module 105 controls the phase shifting module 102 and the radio frequency amplification module 103 respectively, performs phase modulation and amplification processing on the electromagnetic signal received by the smart reflector 101, and then transmits it to the smart reflector 101 along the original path, which is reflected to the user end according to the target reflection angle; the electromagnetic signal received by the user end is received and analyzed by the information acquisition module 501 in the negative feedback module 104, and the instruction is transmitted to the back-end control module 105. The back-end control module 105 adjusts the reflection coefficient of the radio frequency amplification module 103 according to the feedback signal;

[0067] The smart reflective surface 101 is used to receive and reflect electromagnetic signals. Specifically, the back-end control module 105 adjusts the phase shift module 102 and the RF amplification module 103 to change the phase and amplitude of the electromagnetic signal. Each patch unit 204 receives and reflects the dual-frequency signal through the phase shift module 102.

[0068] After the phase shift module 102 is electrically connected to the smart reflector 101, the phase of the incident electromagnetic signal can be adjusted. The sub-frequency module 301 selection of the phase shift module 102 can be controlled by the radio frequency switch 302 to achieve regulation of the incident electromagnetic signal at different frequencies;

[0069] The RF amplification module 103 changes the amplitude of the incident electromagnetic signal. After the RF amplification module 103 is electrically connected to the phase shift module 102, the phase-changed electromagnetic signal is passed through the dynamic gain adjustment unit 402 to achieve amplitude control of the electromagnetic signal. The back-end control module 105 can achieve amplitude control of electromagnetic signals at different frequencies through the frequency coordinator 407. The modulated electromagnetic signal is transmitted back to the smart reflective surface 101 through the original path from the input / output port 405, and the modulated target electromagnetic signal is reflected to the user end.

[0070] Negative feedback module 104 monitors the user end in real time, detects the signal quality of the communication system, calculates the error signal, and implements adaptive adjustment of the system. Information acquisition module 701 collects the return signal from the user end. Adaptive algorithm module 702 compares the calculated estimated error signal with the target parameter. Control signal generation module 704 generates a control signal to backend control module 105 for coordinated control of RF amplification module 103.

[0071] The back-end control module 105 plays a core control role in the entire communication system. It combines the real-time monitoring of electromagnetic signals at the user end and the negative feedback signal to achieve dynamic state adjustment, store discrete codebooks, realize directional reflection of electromagnetic signals, and control the path selection, amplification state control, and frequency selection of the phase shift module 102 and the RF amplification module 103 respectively. It coordinates with the negative feedback module 104 to control the communication system and achieve stability of information transmission in the communication system.

[0072] like Figure 2 As shown, the smart reflective surface 101 includes: a reflective unit array 201, a dielectric layer 202, a reflective back plate 203, a connecting through hole 205 and a connecting port 206;

[0073] The reflective unit array 201 is provided on the front surface of the dielectric layer 202 to receive and reflect incident electromagnetic signals. The reflective unit array is composed of a plurality of patch units 204. The number and arrangement of the patch units 204 can be adjusted according to the actual application scenario. The patch units 204 are used to receive or reflect electromagnetic signals.

[0074] The phase and amplitude of the incident electromagnetic signal received by the patch unit 204 can be controlled in finite steps by the phase shift module 102 and the RF amplification module 103 , and can be configured by the backend control module 105 according to the azimuth angles of the incident signal and the reflected signal.

[0075] In this embodiment, the patch unit 204 adopts a double-layer structure to expand the bandwidth of the device receiving electromagnetic signals. The double-layer structure of the patch unit 204 is achieved by introducing a sub-dielectric layer 207 on the dielectric layer 202.

[0076] In this embodiment, the patch unit 204 is further provided with a connecting through hole 205, which passes through the reflective backplane 203 and matches the connecting port 206 to enable the phase shift module 102 and the RF amplification module 103 to actively feed the patch unit 204.

[0077] In this embodiment, the connection port 206 is provided on the reflective backplane 203 and is connected to the first connection port 303 of the phase shift module. The second connection port 310 of the phase shift module is then connected to the input / output port 405 of the RF amplification module. After the smart reflective surface 101 receives the signal, it is transmitted to the phase shift module for phase modulation and then to the RF amplification module for reflection amplification. Only after passing through the RF amplification module can the signal return to the smart reflective surface 101. The reflective backplane 203 is provided on the back side of the dielectric layer 202 and is made of thick copper to reduce reverse leakage waves.

[0078] like Figure 3As shown, the phase shift module 102 includes: two sub-frequency modules 301, a plurality of first RF switches 302, a first connection port 303, a second connection port 310 and a DC power control port 304;

[0079] The first connection port 303 is connected to the smart reflective surface and the RF amplification module respectively, and is used to transmit the received electromagnetic signal captured by the smart reflective surface. The DC power supply control port is connected to the back-end control module to control the state switching of the RF switch;

[0080] The number of phase shift modules 102 corresponds to the number of patch units 204. The first connection port 303 of the phase shift module 102 is connected to the connection port 206 of each patch unit 204, serving as a feeding port for each patch unit 204.

[0081] In this embodiment, the first radio frequency switch 302 is a single-pole double-throw switch, which switches the connection path of the electric shock through the back-end control module 105 to control the switching of the phase shift circuit of different frequencies;

[0082] In this embodiment, the operating frequency of the phase shift module 102 is set at 1.8GHz and 2.4GHz. When the RF switch 302 is just connected and not started, the single pole of the switch is connected to the 1.8GHz frequency module contact by default. The DC power supply is connected through the DC power control port 304, and the control of the DC power supply is connected to the back-end control module as the switching control of the first RF switch 302. When a high level is connected, the first RF switch 302 is placed in the 2.4GHz frequency module to achieve phase change of the incident electromagnetic signal of 2.4GHz; when a low level is connected, the RF switch 302 is placed in the 1.8GHz frequency module to achieve phase change of the incident electromagnetic signal of 1.8GHz;

[0083] In this embodiment, the sub-frequency module 301 is composed of four second RF switches 307 and a first reference path 305, a second reference path 308, a first delay path 306, and a second delay path 309 formed by microstrip lines. By changing the length of the microstrip line, the phase of the signal can be adjusted. When a signal propagates in a microstrip line, its phase change is related to the propagation constant β, the signal wavelength λ, and the microstrip line length L. The phase change Δφ of the signal propagating in the microstrip line can be expressed as:

[0084] Δφ=β·L

[0085] in, λ is the wavelength of the signal in the microstrip line, and L is the length of the microstrip line. As can be seen, when a signal propagates in a microstrip line, the phase change is proportional to the length of the microstrip line. Increasing the length of the microstrip line increases the phase delay of the signal, while decreasing the length of the microstrip line decreases the phase delay. By using different microstrip line lengths in the two sub-frequency modules, different signal phase differences can be achieved at different operating frequencies.

[0086] When the first delay path 306 is longer than the first reference path 305 When the second delay path 309 is longer than the second reference path 308, a phase delay of 45° can be achieved; when the second delay path 309 is longer than the second reference path 308 In this embodiment, by switching four RF switches, the first reference path 305 and the second reference path 308, and the first delay path 306 and the second delay path 309 are combined to achieve phase changes of 0°, 45°, 90°, and 135°.

[0087] like Figure 4 As shown, the radio frequency amplification module 103 includes: a single input and output basic amplification circuit 401, a dynamic gain adjustment unit 402, an input / output port 405 and a frequency domain tuner 407;

[0088] In this embodiment, the single-input-output basic amplifier circuit 401 is composed of a radio frequency transistor 403 , a DC blocker 404 , a bias power supply 406 , a microstrip line 408 , a radio frequency resistor 409 , and a radio frequency bypass capacitor 410 .

[0089] The input / output port 405 is connected to the phase shift module to receive the phase-modulated electromagnetic signal. The electromagnetic signal is amplified by the radio frequency amplification module and then transmitted back to the smart reflective surface through the same port for reflection.

[0090] The gate of the RF transistor 403 is directly connected to the input / output port 405, which inputs a phase-modulated incident electromagnetic signal. Therefore, the RF transistor 403 adopts an N-channel junction field-effect transistor. When the gate is not connected to a power supply, the device is in a normal conducting state. The source is grounded through a parallel circuit consisting of a microstrip line 408, an RF resistor 409, and an RF bypass capacitor 410, providing a static operating point for the RF transistor 403 and a current negative feedback path. The microstrip line 408 is connected to the source as an inductor device, so that the amplifier circuit operates in an unstable range and the input resistance is negative.

[0091] The DC blocker 404 is implemented in the form of parallel RF capacitors. At high frequencies, electromagnetic signals are highly sensitive to equivalent series resistance (ESR). The ESR of a single capacitor can lead to signal attenuation and heat generation. Furthermore, in this embodiment, the RF amplifier circuit must operate within a wide bandwidth. To avoid signal resonance, a redundant design is employed to improve electromagnetic signal transmission efficiency while broadening bandwidth coverage.

[0092] In this embodiment, the dynamic gain adjustment unit 402 adjusts the amplification factor of the RF amplification module 103, increases the amplitude of the signal, and can switch between three amplification states, namely, amplification state 0, amplification state 1, and amplification state 2, thereby changing the input impedance of the connected amplifier circuit to achieve a change in the reflection gain coefficient value, thereby enabling the RF amplification module to have different amplification gains;

[0093] The first microstrip line 4001 with different impedance values is connected to the second microstrip line 4002, the third microstrip line 4003, and the fourth microstrip line 4004 respectively through Schottky diodes. The back-end control module 105 controls the connection of the DC power supply to the connection point 1, the connection point 2, and the connection point 3, that is, the conduction of the diodes of each microstrip line, to change the impedance value of the connected amplifier circuit, so that the radio frequency amplifier module can operate at different frequencies;

[0094] When the RF amplifying module 103 is in amplifying state 0, connection point 1 is connected to a DC power supply, and connection point 2 and connection point 3 are not connected to a DC power supply; when the RF amplifying module 103 is in amplifying state 1, connection point 2 is connected to a DC power supply, and connection point 1 and connection point 3 are not connected to a DC power supply; when the RF amplifying module 103 is in amplifying state 2, connection point 3 is connected to a DC power supply, and connection point 1 and connection point 2 are not connected to a DC power supply;

[0095] In this embodiment, the frequency domain tuner 407 serves to adjust the frequency of the electromagnetic signal amplified by the RF amplification module 103, so that signals at two operating frequencies, 1.8 GHz and 2.4 GHz, can be amplified, and the operating frequency at which the received signal is located is selected, thereby achieving the required ratio of load impedance to input impedance and obtaining the required reflection amplification factor; the fifth microstrip line 4005 and the sixth microstrip line 4006 are connected through a Schottky diode, and a connection point 4 is drawn out at the positive end of the Schottky diode, and the connection between the DC power supply and the connection point 4 is controlled by the back-end control module 105. When the RF amplification module needs to be at a 1.8 GHz operating frequency, the connection point 4 is not connected to the DC power supply, the Schottky diode is not turned on, and only the microstrip line 4005 participates in amplification; when the RF amplification module needs to be at a 2.4 GHz operating frequency, the connection point 4 is connected to the DC power supply, the Schottky diode is turned on, and both the microstrip line 4005 and the microstrip line 4006 participate in amplification;

[0096] The reflection gain coefficient of the RF amplifier module is expressed as:

[0097]

[0098] Among them, Z0 is the load impedance connected to the RF amplifier module, Z in Is the input impedance of the RF amplifier module. in When infinitely approaching -Z0, the reflection gain coefficient |Γ| 2 Approaches infinity. However, in order to reduce the signal-to-noise ratio and avoid oscillation of the RF amplifier module, Z in The value of needs to maintain a certain difference with -Z0. When the reflection gain coefficient is maintained stable in the range of |Γ|>1, the RF amplification module can achieve the effect of amplifying reflection.

[0099] like Figure 5 and Figure 6 As shown in FIG, the simulation results show the amplification performance of the RF amplification module 103 when the RF amplification circuit operates at 1.8 GHz and 2.4 GHz respectively. Since the RF amplification module 103 adopts a single input and output amplification circuit, the S(1,1) parameter is used to describe the electromagnetic signal amplification parameters of the RF amplification module 103. Figure 5 As shown, when the RF amplification module 103 operates at a frequency of 1.8 GHz, that is, only the microstrip line 4005 participates in amplification, the power amplifier can reach 16.488 dB; when the RF amplification module 103 operates at a frequency of 2.4 GHz, that is, when the connection point 4 is connected to a DC power supply and both the microstrip line 4005 and the microstrip line 4006 participate in amplification, the power amplifier can reach 17.625 dB.

[0100] like Figure 7 As shown, the negative feedback module 104 includes: an information acquisition module 701, an adaptive algorithm module 702, an error calculation module 703, and a control signal generation module 704;

[0101] In this embodiment, to ensure that the negative feedback module can accurately obtain electromagnetic signal information from the user end, the signal acquisition module 701 uses a dual-band coupler with a switchable bandpass filter bank to ensure that the module can operate at both 1.8 GHz and 2.4 GHz operating frequencies. It also uses an IQ demodulator to extract the electromagnetic signal from the user end and separate the amplitude and phase information of the signal. This prepares parameters for the subsequent error calculation module 703 to facilitate accurate calculation of the error signal value.

[0102] In this embodiment, the error calculation module 703 needs to perform error calculation on the electromagnetic signal collected from the user terminal. For the storage of target values, the parameter threshold and phase reference of the target electromagnetic signal are stored in EEPROM as a reference standard. And according to the following formula:

[0103] ΔA=|A1-A0|

[0104] ΔΦ=|Φ1-Φ0|

[0105] E=αΔA+βΔΦ

[0106] Where A1 is the actual input electromagnetic signal amplitude, A0 is the set reference electromagnetic signal amplitude, ΔA is the electromagnetic signal amplitude error, Φ1 is the actual input electromagnetic signal phase value, Φ0 is the set reference electromagnetic signal amplitude, ΔΦ is the electromagnetic signal phase error, and E is the combined error obtained by weighting the ΔA electromagnetic signal amplitude error and the ΔΦ electromagnetic signal phase error. When the error calculation module 703 is started, the target parameters required to be achieved at the current operating frequency must be input and stored. After the electromagnetic signal at the user end is separated into amplitude and phase values by the information acquisition module 701, the amplitude error and phase error of the electromagnetic signal are calculated according to the above formulas, and the obtained values are transmitted to the adaptive algorithm module 702.

[0107] In this embodiment, the adaptive algorithm module 702 adopts FPGA parallel computing architecture to reduce the overall algorithm response speed and realize real-time control of signal amplification parameters. - , E + ], the control signal generating module 704 does not generate an instruction to change the radio frequency amplifying module, wherein [E - , E + ] is the acceptable error range;

[0108] In this embodiment, the control signal generation module 704 converts the algorithm output into a physical control signal, driving the back-end control module 105 to regulate the RF amplification module 103. The RF amplification module 103 has three amplification states: amplification 0, amplification 1, and amplification 2. The adaptive algorithm module 702 uses the algorithm logic to determine the signal to be sent, and the control signal generation module 704 coordinates to achieve switching between the three amplification states.

[0109] like Figure 8 As shown, in order to clearly illustrate the working logic of the adaptive algorithm module 702, a systematic judgment operation standard is proposed. The three amplification states of amplification state 0, amplification state 1 and amplification state 2 are specifically manifested as an increasing trend in the amplification factor of the signal amplitude. First, when the overall system is initially operated, the negative feedback module 104 sends a state hold signal to the back-end control module 105; secondly, when the overall system is operating stably, the information acquisition module 701 collects the electromagnetic signal of the user end and transmits it to the error calculation module 703 for estimated error calculation, and the estimated error signal E of the calculation result is transmitted to the adaptive algorithm module 702; further, when the error signal E transmitted by the receiving error calculation module 703 is [E- , E + ], here E + >0, E-<0. The control signal generation module 704 does not generate an instruction to change the RF amplification module; if the error signal E>E + , indicating that the current amplification factor of the RF amplification module 103 is too large, which causes the control signal generation module 704 to generate a signal to reduce the amplification factor, and connect the previous level connection point of the current connection point to the power supply, that is, the connection point with a smaller amplification factor than the current amplification factor state; if E<E - When E 1- <E<E - When E<E 1- When |E|<|E 1- |, the control signal generation module 704 generates a signal to the back-end control module 105, adjusting the RF amplification module 103 to the amplification state 1; if |E|>|E 1- |, the control signal generating module 704 generates a signal to the back-end control module 105, adjusts the RF amplification module 103 to the amplification state 2, and dynamically adjusts until the value of the error signal E is within the acceptable range [E - , E + ];

[0110] like Figure 9 As shown, the back-end control module 105 includes: a central processing unit module 901, and a phase shift state control module 902, a radio frequency amplification frequency control module 903, a radio frequency amplification factor control module 904, an external control module 905, a discrete codebook control module 906 and a negative feedback receiving module 907 respectively connected to the central processing unit module 901;

[0111] The phase shift state control module 902 is used to control the operating frequency selection of the phase shift module 102, that is, the selection of the sub-frequency module 301 and the combination of the reference path and the delay path in the sub-frequency module 301, and to achieve different phase shift controls by controlling the switching of the first RF switch 302;

[0112] The RF amplification frequency control module 903 is used to control the operating frequency selection of the RF amplification module 103 and control the connection relationship between the connection point 4 and the DC power supply. When the operating frequency is required to be 1.8 GHz, the connection point 4 is not connected to the DC power supply; when the operating frequency is required to be 2.4 GHz, the connection point 4 is connected to the DC power supply.

[0113] The RF amplification factor control module 904 is used to control the amplification state selection of the RF amplification module 103. The RF amplification factor control module 103 has three amplification states, namely amplification state 0, amplification state 1, and amplification state 2. When in amplification state 0, the RF amplification factor control module 904 connects the connection point 1 to the DC power supply to connect the first microstrip line 4001 and the first microstrip line 4002; when in amplification state 1, the RF amplification factor control module 904 connects the connection point 2 to the DC power supply to connect the first microstrip line 4001 and the third microstrip line 4003; when in amplification state 2, the RF amplification factor control module 904 connects the connection point 3 to the DC power supply to connect the first microstrip line 4001 and the fourth microstrip line 4004.

[0114] The external control module 905 is a port used by the operator when the external intervention device is running. It can be used to monitor the system operation in real time through an external display device and retain an effective interactive interface for direct intervention by the operator;

[0115] The discrete codebook control module 906 is used to manage the entered codebook information. The codebook corresponding to the target reflection angle is pre-entered into the discrete codebook control module 906. When the electromagnetic signal is reflected, the codebook is directly called to change the state of the phase shift module 102 and the radio frequency amplification module 103 external to each reflection unit array 201.

[0116] The negative feedback receiving module 907 is used to receive the signal transmitted by the control signal generating module 704 in the negative feedback module 104, so as to change the amplification state of the RF amplifying module 103. - , E + ], the control signal generating module 704 does not generate an instruction to change the RF amplifying module, the negative feedback receiving module 907 keeps the RF amplifying module 103 in amplifying state 0, and the connection points 1, 2 and 3 are not connected to the DC power supply; if the error signal E>E + , indicating that the current amplification factor of the RF amplification module 103 is too large, which causes the control signal generation module 704 to generate a signal to reduce the amplification factor, connect the connection point of the previous level of the current connection point to the power supply, and the negative feedback receiving module 907 changes the connection between the connection point and the DC power supply; if E<E - When |E|<|E 1- |, the control signal generation module 704 generates a signal to the negative feedback receiving module 907 of the back-end control module 105, connects the connection point 2 to the DC power supply, and adjusts the RF amplification module 103 to the amplification state 1; if |E|>|E 1-|, the control signal generating module 704 generates a signal to the negative feedback receiving module 907 of the back-end control module 105, connects the connection point 3 to the DC power supply, and adjusts the RF amplification module 103 to the amplification 2 state, and dynamically adjusts until the value of the error signal E is within the acceptable range [E - , E + ].

[0117] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation, characterized in that: include: Intelligent reflective surface, phase shift module, RF amplification module, negative feedback module and back-end control module; The smart reflective surface is connected to the phase shifting module, the phase shifting module is connected to the radio frequency amplification module, the back-end control module is connected to the phase shifting module and the radio frequency amplification module respectively, the smart reflective surface is connected to the negative feedback module, and the negative feedback module is connected to the back-end control module; The intelligent reflective surface receives electromagnetic signals, adjusts the phase of the electromagnetic signals through the phase shifting module, and adjusts the amplitude of the electromagnetic signals through the radio frequency amplification module, and transmits them to the intelligent reflective surface. The intelligent reflective surface reflects the electromagnetic signals after phase modulation and amplification to the user end. The negative feedback module receives the return electromagnetic signals from the user end, calculates and compares the estimated error signals with the target parameters, generates negative feedback signals and transmits them to the back-end control module. The back-end control module controls the phase shifting module and the radio frequency amplification module to perform phase modulation and amplification processing respectively to achieve directional reflection of the electromagnetic signals.

2. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 1, characterized in that: The smart reflective surface comprises: a reflective unit array, a dielectric layer, a reflective backplane and a connection port; The reflective unit array is arranged on the front side of the dielectric layer, and the reflective unit array is composed of a plurality of patch units, and the patch units are used to receive or reflect electromagnetic signals; The reflective back plate is arranged on the back side of the dielectric layer, the connection port is arranged on the reflective back plate, and the connection port is connected to the phase shift module.

3. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 2, characterized in that: The patch unit is further provided with a connecting through hole, which passes through to the reflective back plate and matches and corresponds to the connecting port, so as to enable the phase shift module and the radio frequency amplification module to actively feed it.

4. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 1, characterized in that: The phase shift module includes a sub-frequency module, a radio frequency switch, a first connection port, a second connection port and a DC power supply control port; The first connection port is connected to the smart reflective surface and the radio frequency amplification module respectively, and is used to transmit the electromagnetic signal received by the smart reflective surface; The first connection port is connected to a radio frequency switch, and the radio frequency switch is respectively connected to sub-frequency modules of different operating frequencies; The RF switch is also connected to a DC power supply control port, which is connected to a back-end control module. The back-end control module controls the state switching of the RF switch, accesses a sub-frequency module corresponding to the operating frequency, and realizes phase change of the incident electromagnetic signal. The radio frequency switch is connected to the second connection port, and the second connection port is connected to the radio frequency amplification module.

5. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 4, characterized in that: The sub-frequency module includes: four RF switches, a first reference path, a second reference path, a first delay path, and a second delay path; The first reference path, the second reference path, the first delay path, and the second delay path are composed of microstrip lines of different lengths; An RF switch is provided at both ends of the first reference path and the first delay path, respectively; an RF switch is provided at both ends of the second reference path and the second delay path, respectively. By switching the four RF switches, the first reference path and the second reference path, the first delay path and the second delay path are combined to achieve phase delays of different angles.

6. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 5, characterized in that: The phase change of a signal propagating in a microstrip line is expressed as: Δφ=β·L Where Δφ represents the phase change, β represents the propagation constant, λ represents the signal wavelength, and L represents the length of the microstrip line. When the first delay path 306 is longer than the first reference path 305 When , a phase delay of 45° is achieved; When the second delay path 309 is longer than the second reference path 308 When , a phase delay of 90° is achieved; By switching four RF switches, the first reference path and the second reference path, and the first delay path and the second delay path are combined to achieve phase changes of 0°, 45°, 90°, and 135°.

7. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 1, characterized in that: The RF amplifier module includes: input / output ports, RF transistors, DC blockers, bias power supplies, microstrip lines, RF resistors and RF bypass capacitors; The input / output port is connected to the phase shift module to receive the phase-modulated electromagnetic signal, which is amplified by the radio frequency amplification module and then transmitted back to the smart reflective surface through the same port for reflection; The gate of the radio frequency transistor is connected to the input / output port, the source of the radio frequency transistor is grounded through a microstrip line and a parallel circuit, the parallel circuit is composed of a radio frequency resistor and a radio frequency bypass capacitor in parallel, the drain of the radio frequency transistor is connected to a DC blocker, and the DC blocker is connected to a bias power supply; The gate of the radio frequency transistor is also connected to a dynamic gain adjustment unit for adjusting the amplification factor of the radio frequency amplification module; The drain of the radio frequency transistor is also connected to a frequency domain tuner for adjusting the frequency of the electromagnetic signal amplified by the radio frequency amplification module.

8. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 7, characterized in that: The dynamic gain adjustment unit is provided with a first microstrip line, a second microstrip line, a third microstrip line, and a fourth microstrip line having different impedance values; The first microstrip line is connected to the second microstrip line, the third microstrip line, and the fourth microstrip line respectively through corresponding Schottky diodes. The back-end control module controls the DC power supply to turn on the Schottky diodes corresponding to each microstrip line, thereby changing the impedance value of the access amplifier circuit so that the RF amplifier module operates at different frequencies. The frequency domain tuner is provided with a fifth microstrip line and a sixth microstrip line, which are connected via a Schottky diode. The back-end control module controls a DC power supply to turn on the Schottky diode, thereby changing the impedance value of the microstrip line involved in amplification at different operating frequencies.

9. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 1, characterized in that: The negative feedback module includes an information acquisition module, an adaptive algorithm module, an error calculation module, and a control signal generation module; The information acquisition module is used to collect the electromagnetic signal returned by the user end, using a dual-band coupler with a switchable bandpass filter group, and an IQ demodulator to extract the electromagnetic signal from the user end and then separate the amplitude and phase information of the signal; The error calculation module is used to perform error calculation on the electromagnetic signal returned from the user end, calculate the amplitude error and phase error of the electromagnetic signal respectively, and weight them to obtain a comprehensive error, which is then transmitted to the adaptive algorithm module; The adaptive algorithm module is used to set an acceptable error range and output a switching control signal of the amplification state according to the relationship between the comprehensive error and the acceptable error range; The control signal generation module is used to convert the switching control signal output by the adaptive algorithm module into a physical control signal, and drive the back-end control module to regulate the radio frequency amplification module.

10. The dual-frequency phase reconfigurable active intelligent reflector system with negative feedback regulation according to claim 1, characterized in that: The back-end control module includes: a central processing unit module, and a phase shift state control module, a radio frequency amplification frequency control module, a radio frequency amplification factor control module, an external control module, a discrete codebook control module and a negative feedback receiving module respectively connected to the central processing unit module; The phase shift state control module is used to control the operating frequency of the phase shift module; The radio frequency amplification frequency control module is used to control the operating frequency selection of the radio frequency amplification module; The radio frequency amplification control module is used to control the amplification state selection of the radio frequency amplification module; The external control module is used to provide an interactive interface; The discrete codebook control module is used to store the codebook corresponding to the reflection angle of the target, and call the codebook to change the state of the phase shift module and the radio frequency amplification module when the electromagnetic signal is reflected; The negative feedback receiving module is used to receive the transmission signal of the negative feedback module to realize the change of the amplification state of the radio frequency amplification module.

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