An independently addressable control device based on a continuous phase modulation intelligent metasurface

Abstract

The application provides an independently addressable control device based on a continuously phase-modulated intelligent metasurface, which maps the arrangement position information of a metasurface subunit on the metasurface into a logical address in a control program, thereby independently addressing each subunit and further realizing independent addressable operation of the subunit, so that the subunits in certain areas can be continuously regulated by programming, thereby realizing precise and flexible regulation of the intelligent metasurface and making the control effect better. The device mainly comprises three modules connected in sequence: a signal control module for running a pre-set control program to generate a control signal; a signal processing module for outputting multiple independent continuous analog voltages to the metasurface subunit and addressing each output through a global pointer register; and an intelligent reflecting surface module composed of phase-continuously-adjustable metasurface units arranged regularly on a circuit board.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless communication, and relates to an independently addressable control device based on a continuous phase modulation intelligent metasurface. BACKGROUND

[0002] An intelligent metasurface is a two-dimensional artificial material with subwavelength size, which is usually composed of metal, dielectric and adjustable elements, and can be equivalent to an RLC circuit. By adjusting the physical properties of the electromagnetic unit, such as capacitance, impedance or inductance, the radiation characteristics of the RIS are changed, and very unconventional physical phenomena such as irregular reflection, negative refraction, wave absorption, focusing and polarization conversion are realized, thereby dynamically regulating electromagnetic waves. Because it can flexibly manipulate electromagnetic properties in the channel environment, it provides a new paradigm for the design of communication systems, and intelligent metasurfaces have become one of the promising key technologies in future 6G, attracting widespread attention from academia and industry. An intelligent metasurface is usually composed of a large number of carefully designed electromagnetic units, and by applying a control signal to the adjustable elements on the electromagnetic units, the electromagnetic properties of these electromagnetic units can be dynamically controlled, thereby actively and intelligently controlling the spatial electromagnetic waves in a programmable manner to form an electromagnetic field with controllable amplitude, phase, polarization and frequency.

[0003] Traditional subwavelength near-passive scattering units have a limited number of unit states, and the reflection phase also has a limited number of values. The limited number of unit states will result in insufficient beamforming accuracy, affecting communication effectiveness. If the number of unit states is increased to improve beam accuracy, there will be a large control cost, and as the number of unit states increases, the anti-interference ability of the intelligent metasurface will also be weakened. The basic subunit is generally composed of metal, dielectric and adjustable devices. When the number of designed intelligent metasurface subunits is determined, the number of states of the basic unit of the intelligent metasurface is also determined, and the phase accuracy that can be adjusted by the intelligent metasurface is also determined. Under different phase accuracy requirements, the intelligent metasurface is difficult to meet the requirements.

[0004] For an intelligent metasurface with continuous phase modulation, the reflection phase can be continuously varied, and the phase accuracy of the reflected electromagnetic wave can be adjusted. However, for an intelligent metasurface containing a large number of subunits, the control difficulty is great, and in order to simplify the control method, all subunits in a certain row or column of the intelligent metasurface generally share one control voltage, so its control ability is significantly reduced, and it is difficult to achieve precise control according to the scene requirements. SUMMARY

[0005] The application provides an independently addressable control device based on a continuously phase-modulated intelligent metasurface, which maps the arrangement position information of a metasurface subunit on the metasurface into a logical address in a control program, and can realize independent addressing and continuous control of the metasurface subunit through programming, without increasing the number of unit states, and can provide high-precision beam control, improve the working efficiency of the intelligent metasurface, and expand the application scenarios.

[0006] The device comprises a signal control module, a signal processing module, and a continuously phase-modulated intelligent metasurface module.

[0007] The signal control module is configured to run a pre-set control program, generate a control signal, and input the control signal to the signal processing module.

[0008] The signal processing module is configured to output multiple independent and continuous analog voltage signals, and each voltage output is connected to a corresponding subunit in the intelligent metasurface. Each data register corresponding to each digital-to-analog conversion circuit is addressed through a global pointer register, and then each subunit corresponding to each digital-to-analog conversion circuit is addressed.

[0009] The continuously phase-modulated intelligent metasurface module is composed of phase-continuously-adjustable reflection units arranged regularly on a circuit board.

[0010] In operation, the bias voltage applied to the continuously phase-modulated unit is changed, and then the phase of the unit is changed, so that the electromagnetic waves reflected by different reflection units have different reflection coefficients, and the reflection coefficients can be continuously changed with the change of the bias voltage.

[0011] Further, the signal control module can read and write access the registers in the signal processing module through an I / O interface.

[0012] Further, the signal control module can be implemented by a programmable chip.

[0013] Further, the signal processing module comprises a global pointer register, a data register, and n R-2R digital-to-analog conversion circuits, where n is equal to the number of subunits in the intelligent metasurface.

[0014] The global pointer register is configured to store the address of the data register corresponding to each R-2R digital-to-analog conversion circuit, and the signal control module can address each analog voltage output and then address the corresponding metasurface subunit by accessing the global pointer register. When the signal control module accesses the data register corresponding to a certain R-2R digital-to-analog conversion circuit, the global pointer register stores the address of the current access, and the signal control module can access different data registers by modifying the value in the global pointer register.

[0015] Optionally, the global pointer register is used to address the data register corresponding to each R-2R digital-analog conversion circuit, which is beneficial to simplify the register structure of the information processing module and reduce the hardware cost.

[0016] Optionally, the global pointer register stores the address information of each output voltage, and the information control module can divide the intelligent metasurface into multiple sets by addressing the position information, each set including a plurality of metasurface subunits with similar position information. Dividing the intelligent metasurface into multiple sets can improve the control efficiency of large-scale metasurfaces.

[0017] The data register is used to realize data buffering, and the signal control module controls the R-2R digital-analog conversion circuit to convert the digital voltage signal into an analog voltage signal by writing data into the data register.

[0018] Optionally, the signal control module can control whether the signal processing module has voltage output by whether writing data into the data register, and then the trigger mechanism can be added to the metasurface subunit in the control program. When the metasurface subunit at some position has no gain effect on user communication, the voltage at this position can be selected not to be output, thereby improving the stability of the system.

[0019] The n-way R-2R digital-analog conversion circuit is connected with an external direct current voltage source to convert the digital voltage in the data register into an analog voltage and output to the corresponding subunit of the intelligent metasurface.

[0020] Further, the R-2R digital-analog conversion circuit includes a resistor network, an operational amplifier, and a reference voltage source.

[0021] The resistor network is composed of an n-bit R-2R structure, which requires n-1 R resistors and n+1 2R resistors. The R-2R ladder network can significantly reduce the number of resistors in the digital-analog conversion circuit.

[0022] The operational amplifier is added at the voltage output end of the resistor network as the output stage of the digital-analog conversion circuit, so that the digital-analog converter has a certain driving capability.

[0023] The reference voltage source provides a reference voltage for the R-2R digital-analog conversion circuit.

[0024] Optionally, the R-2R digital-analog conversion circuit can not only convert digital signals into analog voltage signals, but also can realize different conversion precisions by adding or reducing the number of resistors to meet the phase control precision requirements in different scenarios.

[0025] Further, the continuously phase-controllable intelligent metasurface module is composed of continuously phase-controllable devices.

[0026] Further, the continuously phase-modulated device is a varactor diode, the capacitance of which changes with the reverse bias voltage applied to the varactor diode, and the electromagnetic wave reflected on the subunit has different reflection coefficients, and the reflection coefficient continuously changes with the change of the bias voltage.

[0027] Optionally, the continuously phase-modulated intelligent metasurface subunit structure comprises a ground metal layer, a dielectric layer, a T-shaped metal patch, and a varactor diode. The two T-shaped metal patches are connected through the varactor diode. The T-shaped metal patches are connected through the metal via hole passing through the dielectric layer and the ground metal layer.

[0028] Advantages

[0029] 1. The application provides a continuously phase-modulated intelligent metasurface-based independently addressable control device, wherein the intelligent metasurface unit is a continuously phase-modulated device, the phase of the reflected electromagnetic wave can be continuously adjusted, and the accuracy of the phase of the reflected electromagnetic wave can be adjusted.

[0030] 2. The application provides a continuously phase-modulated intelligent metasurface-based independently addressable control device, which can realize independent control of the intelligent metasurface subunit and improves the control ability.

[0031] 3. The application provides a continuously phase-modulated intelligent metasurface-based independently addressable control device, which maps the position arrangement information of the subunit on the intelligent metasurface into a logical address in a control program, can realize intelligent control by programming, improves the running efficiency of the control program, and can more flexibly regulate and control the intelligent metasurface parameters. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings from the structures shown in the drawings without creative labor.

[0033] Figure 1 is a framework flowchart of the continuously phase-modulated intelligent metasurface-based independently addressable control device provided by the embodiment 1 of the present application;

[0034] Figure 2 is a schematic diagram of the intelligent metasurface provided by the embodiment 1 of the present application;

[0035] Figure 3 is a schematic diagram of the intelligent metasurface structure unit provided by the embodiment 1 of the present application;

[0036] Figure 4These are the phase frequency response curves of the intelligent metasurface structure unit provided in Embodiment 1 of the present invention under different bias voltages;

[0037] Figure 5 This is a schematic diagram of the R-2R digital-to-analog converter circuit provided in Embodiment 1 of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1:

[0040] like Figure 1 As shown, this embodiment provides an independently addressable control device based on a continuously phase-tuning intelligent metasurface. The device includes a signal control module, a signal processing module, and a continuously phase-tuning intelligent metasurface module. These modules are sequentially connected. The signal control module generates a control signal and communicates with the signal processing module. It selects the voltage output channel by accessing a global pointer register, writes voltage data into a data register, and the data register controls an R-2R trapezoidal digital-to-analog converter circuit to convert the digital signal into an analog voltage signal, which is then output to the corresponding sub-unit of the intelligent metasurface. The intelligent metasurface sub-unit is a continuously phase-tunable device; in this example, a varactor diode is chosen as the continuously phase-tunable device. The signal processing module converts the digital signal into an analog voltage signal and applies it to the two ends of the varactor diode, causing the varactor diode to generate different capacitance values. This, in turn, causes the sub-unit of the intelligent metasurface to generate different resonant frequencies, achieving different phase compensations and thus controlling the transmission channel of the reflected electromagnetic wave. In this embodiment, the number of intelligent metasurface sub-units is 12*11=132. The intelligent metasurface can directly manipulate electromagnetic waves. Since each sub-unit has a different compensation phase for the reflected electromagnetic waves, each sub-unit reflects electromagnetic waves with different directions and beamforming shapes. The signal control module obtains different reflection coefficients by adding different control bias voltages to each sub-unit to achieve optimal beamforming of the reflected electromagnetic waves.

[0041] Specifically, the signal control module is implemented by a programmable chip, including a microcontroller, a digital signal processor (Digital Signal Process, DSP) and a field-programmable gate array (Field-Programmable Gate Array, FPGA), etc. In the present example, an FPGA programmable chip is selected, specifically a Xilinx Zynq 7100 model, which communicates with the information processing module through an I / O port to realize read-write access to all registers in the information processing module. The I / O interface can communicate with the registers in the information processing module through a bus protocol, including SPI (Serial Peripheral Interface), IIC (Inter-Integrated Circuit), etc. In the present example, the SPI serial external device interface is used to realize mutual communication between the signal control module and the signal processing module.

[0042] Specifically, the present example uses an FPGA to implement the control program of the intelligent metasurface, and the control program includes a main program module, an SPI communication module and a RAM storage module. In the initialization stage, the data register addresses corresponding to the R-2R digital-to-analog conversion circuit connected to the intelligent metasurface subunit are written in the RAM storage module. In the program running stage, the main program controls the SPI communication module to realize communication with the information processing module. When it is necessary to control a certain channel of the metasurface subunit, the main program reads the corresponding address data from the RAM storage module, and writes the corresponding address data into the global pointer register in the information processing module through the SPI interface protocol. The global pointer register addresses the corresponding data register, and then the main program controls the R-2R digital-to-analog conversion circuit to convert the digital voltage signal into an analog voltage signal by writing digital voltage data into the data register.

[0043] Specifically, the signal processing module includes a global pointer register, a data register and n-channel R-2R digital-to-analog conversion circuit, the value of n is consistent with the number of intelligent metasurface subunits. In the present example, there are 132 intelligent metasurface subunits, so n = 132 R-2R digital-to-analog conversion circuits. When the FPGA accesses the data register corresponding to a certain channel of the R-2R digital-to-analog conversion circuit, the global pointer register stores the current access address. The FPGA can access different data registers by modifying the value in the global pointer register. The data register realizes data buffering, and the FPGA controls the R-2R digital-to-analog conversion circuit to convert the digital signal into an analog voltage by writing data into the data register.

[0044] Specifically, the R-2R digital-to-analog conversion circuit includes a resistance network, an operational amplifier and a reference voltage source. An n-bit R-2R resistance network requires n-1 R resistors and n+1 2R resistors. The present example uses an 8-bit R-2R digital-to-analog conversion circuit. The operational amplifier, as the output stage of the digital-to-analog conversion circuit, is added to the voltage output end of the resistance network, so that the digital-to-analog converter has a certain driving capability. The reference voltage source provides a reference voltage for the R-2R digital-to-analog conversion circuit.

[0045] Specifically, the continuous phase modulation intelligent metasurface module receives an analog voltage signal input from the signal processing module, and realizes the regulation and control of the metasurface subunit. Since the present example uses a varactor diode as a continuous phase modulation device, the regulation and control of the varactor diode capacitance value is realized. By controlling the reverse bias voltage across the varactor diode, the capacitance value is dynamically changed, thereby changing the resonant frequency of the metasurface subunit. Different resonant frequencies realize different phase compensation angles, and finally realize beam forming of reflected electromagnetic waves.

[0046] Specifically, the structure of the intelligent metasurface subunit in the present example includes a ground metal layer, a dielectric layer, a T-shaped metal patch and a varactor diode. The two T-shaped metal patches are connected by a varactor diode. The T-shaped metal patch is connected through a metal via hole through the dielectric layer and the ground metal layer.

[0047] Embodiment 2:

[0048] In the application scenario of user communication assisted by an intelligent metasurface, the user is at a certain position in the service area of the intelligent metasurface. Due to the randomness of the user's position, it is difficult to calculate the phase compensation of each subunit when the intelligent metasurface serves this user, and it is difficult to obtain the corresponding reflection coefficient, so the control end cannot effectively output the corresponding bias voltage. The present application provides an independently addressable control device based on a continuous phase modulation intelligent metasurface, which maps the position information of the subunit on the intelligent metasurface into a logical address in the control program. An automatic traversal algorithm program is run on the control end, and the reflection coefficient is quickly calculated in combination with user feedback, thereby realizing beam forming of reflected electromagnetic waves.

[0049] Optionally, when different users have different requirements for beam control accuracy, the control end can sequentially traverse each subunit of the intelligent metasurface, continuously phase modulate each subunit, or select subunits with similar positions as a whole and output a control voltage, thereby meeting the different requirements of different users for beam control accuracy.

[0050] Optionally, the control end can traverse the sub-units on the intelligent metasurface, output each voltage in turn, and observe the signal receiving power or signal-to-noise ratio of the user end. If the voltage can produce gain on the signal receiving power or signal-to-noise ratio of the user, the output of this path is activated; if there is no gain, the output of this path is closed, thereby improving the working efficiency of the intelligent metasurface and reducing energy consumption.

[0051] In summary, the application provides an independently addressable control device based on a continuously phase-modulated intelligent metasurface. By mapping the position arrangement information on the intelligent metasurface into the logical address in the control program, any sub-unit on the intelligent metasurface can be independently addressed. The intelligent programming is used to achieve more flexible control and meet different application requirements supported by the intelligent metasurface. Since the sub-units in the intelligent metasurface are continuously phase-modulated devices, continuous phase compensation can be achieved, that is, continuous channel control can be performed to ensure high-precision beam forming.

[0052] Although the above describes the illustrative specific embodiments of the application in order to facilitate the understanding of the application by those skilled in the art, it should be clear that the application is not limited to the scope of the specific embodiments, and for those skilled in the art, any changes within the spirit and scope of the application defined and determined by the appended claims are obvious, and all the application creations using the concept of the application are included in the protection.

Claims

1. An independently addressable control device based on a continuous phase modulation intelligent metasurface, characterized in that, The intelligent metasurface comprises a signal control module, a signal processing module and a continuously phase-modulated intelligent metasurface module connected in sequence. The signal control module is used for running a control program and is realized by a programmable chip and communicates with the signal processing module through an I / O interface. The signal processing module comprises a global pointer register, a data register and an n-way R-2R digital-analog conversion circuit, wherein the value of n is equal to the number of subunits in the intelligent metasurface. The global pointer register is used for addressing the data register corresponding to each way of the R-2R digital-analog conversion circuit, and when the signal control module accesses the data register corresponding to each way of the R-2R digital-analog conversion circuit, the global pointer register stores the current access address, and the signal control module can access different data registers by modifying the value in the global pointer register. The data register is used for realizing data buffering, and the signal control module controls the R-2R digital-analog conversion circuit to convert a digital voltage signal into an analog voltage signal by writing data into the data register. The R-2R digital-analog conversion circuit comprises an R-2R resistance network, an operational amplifier and a reference voltage source, and one n-bit R-2R resistance network needs n-1 R resistors and n+1 2R resistors, and different conversion precisions are realized by adding or reducing the number of resistors, and the specific voltage size is determined by the control coefficient required by the continuously phase-modulated intelligent metasurface subunit. The continuously phase-modulated intelligent metasurface module is composed of phase-continuously-adjustable reflection units arranged regularly on a circuit board, and each subunit is connected with one way of the R-2R digital-analog conversion circuit. The signal control module generates a control signal, communicates with the signal processing module, selects a voltage output channel by accessing the global pointer register, writes voltage data into the data register, and the data register controls the R-2R digital-analog conversion circuit to convert a digital signal into an analog voltage signal and outputs the analog voltage signal to the corresponding subunit of the intelligent metasurface.

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