Electromagnetic sensing system, object attitude electromagnetic sensing method and metasurface structure

Abstract

The embodiment of the invention provides an electromagnetic sensing system, an object attitude electromagnetic sensing method and a metasurface structure, and belongs to the technical field of electromagnetic sensing. The electromagnetic sensing system comprises a metasurface antenna which is used for radiating electromagnetic waves and capturing scattered waves of an object to be detected for the electromagnetic waves; the output end of the active power amplifier is in cascade connection with the metasurface antenna, and the output impedance of the active power amplifier can be changed along with the scattered waves; and the current detection circuit is in cascade connection with the current input end of the active power amplifier and is used for monitoring the current change of the active power amplifier so as to reflect the sensed posture of the object to be detected. According to the invention, the time delay of electromagnetic sensing data processing can be greatly shortened, the sensing speed is greatly improved, and the system cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic sensing technology, and in particular to an electromagnetic sensing system, an object posture electromagnetic sensing method and a super surface structure. Background Art

[0002] Space electromagnetic perception is a technology that detects and perceives the environment and objects through electromagnetic transceiver equipment. It is now widely used in agriculture, medicine, aerospace, aviation, navigation, terrain detection, climate monitoring and other aspects, providing vital technical support for national defense and economic development. Traditional electromagnetic wave detection and perception systems usually use radar, phased array antenna system, multiple input multiple output antenna system and ultra-wideband antenna system for high-precision target detection and perception. In order to reduce electromagnetic interference in the environment, a strong electromagnetic perception system and its use method are disclosed in Chinese invention patent CN118843023A. This method converts the electrical signal received by the ring antenna into an optical signal and uses optical fiber for transmission, thereby reducing transmission loss and reducing environmental interference to enhance the reliability of the entire system. In Chinese invention patent CN109565497A, an environmental perception method based on a base station hardware system is disclosed. By setting the detection cycle of sending electromagnetic perception signals in the base station equipment, the update frequency of environmental information can be dynamically adjusted, thereby meeting the detection requirements of different applications for environmental information. From the perspective of hardware system architecture, traditional electromagnetic perception systems can usually be decomposed into transmitting and receiving parts. The transmitting part consists of multiple functional modules such as digital-to-analog converters, mixers, power amplifiers and filters. The receiving part is usually composed of multiple module circuits such as low-noise amplifiers, mixers, filters, and analog-to-digital converters. Although traditional electromagnetic perception systems can achieve high perception accuracy, they often require complex RF transceiver links, baseband processors, and specific algorithms to detect and perceive environmental objects. The complex hardware architecture leads to high costs and more complex processing algorithms for electromagnetic perception systems, which is not conducive to the further lightweight application of electromagnetic perception technology. In addition, since the longer hardware link increases the time for transmitting electromagnetic signals, it reduces the processor's perception speed of the target object, and there are great limitations on perception rate and processing efficiency. Therefore, the electromagnetic perception system urgently needs to develop new perception technologies with ultra-high speed and low latency response.

[0003] The core of electromagnetic sensing technology is the response and information processing of electromagnetic waves in space. In recent years, with the development of artificial electromagnetic metamaterials and artificial intelligence technology, new technical approaches have been provided for the development of ultra-high-speed and low-latency electromagnetic sensing systems. Compared with traditional radar and large-scale antenna systems, reconfigurable metasurfaces do not require large-scale RF transceiver links and complex system architectures, and because of their flexible spatial electromagnetic control characteristics and simple system composition, they are applied to the recognition and perception of target objects, such as human posture recognition, respiratory monitoring perception, and recognition and manipulation of the surrounding electromagnetic environment. In addition, by adding sensors to the reconfigurable metasurface, real-time beam tracking of moving objects in the environment can be achieved. The above-mentioned reconfigurable metasurface can realize the perception of environmental objects by introducing artificial intelligence algorithms or adding new sensors, but the introduction of artificial intelligence algorithms requires the support of digital signal systems with high sampling rates, and sensors bring additional software and hardware resource requirements and increase the complexity of the overall system. In addition, the echo signals in both methods will be transmitted to the baseband processor through the corresponding RF link, which will cause additional delay response problems. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an electromagnetic sensing system, an electromagnetic sensing method for object posture and a metasurface structure, which can greatly reduce the delay of electromagnetic sensing data processing, greatly improve the sensing speed and reduce the system cost.

[0005] In order to achieve the above object, an embodiment of the present invention provides an electromagnetic sensing system, the electromagnetic sensing system comprising:

[0006] A metasurface antenna, which is used to radiate electromagnetic waves and capture scattered waves of the electromagnetic waves from the object to be measured;

[0007] an active power amplifier, the output end of which is connected in series to the metasurface antenna, and the output impedance of the active power amplifier can vary with the scattered wave; and

[0008] The current detection circuit is connected in series with the current input terminal of the active power amplifier, and is used to monitor the current change of the active power amplifier, and then reflect the perceived posture of the object to be detected.

[0009] Preferably, the current detection circuit comprises:

[0010] a sampling resistor connected in cascade to an input end of the active power amplifier; and

[0011] The digital-to-analog converter is electrically connected to both sides of the sampling resistor and is used to monitor the current change of the active power amplifier, thereby sensing the posture of the object to be measured.

[0012] Preferably, the active power amplifier is integrated into the metasurface antenna.

[0013] In addition, the present invention also provides an electromagnetic sensing method for an object posture, using the above-mentioned electromagnetic sensing system, the electromagnetic sensing method for an object posture comprises:

[0014] The electromagnetic waves radiated by the metasurface antenna generate scattered waves when encountering the object to be measured;

[0015] The scattered waves are captured by the metasurface antenna, thereby changing the output impedance of the power amplifier so as to change the DC supply current of the power amplifier; and

[0016] The posture of the object to be measured is determined according to the change of the DC power supply current.

[0017] Preferably, the scattered wave is captured by the metasurface antenna, and then the output impedance of the power amplifier is changed so that the DC power supply current of the power amplifier is changed, which includes:

[0018] The scattered waves are captured by the metasurface antenna, thereby changing the input reflection coefficient of the metasurface antenna; wherein the output impedance of the power amplifier is configured to be associated with the input reflection coefficient of the metasurface antenna;

[0019] The output power of the power amplifier is configured to be associated with the output impedance, and the output power of the power amplifier is:

[0020]

[0021] Where P is the ratio of the maximum output power of the power amplifier to the back-off output power and satisfies p ≥ 1, Z L and G L is the load impedance and admittance of the amplifier, P opt is the maximum or optimal output power of the power amplifier, X is the load impedance Z L The imaginary part of B is the load admittance G L The imaginary part, R opt G is the optimal output impedance corresponding to the maximum power output of the power amplifier. opt It is the optimal output admittance corresponding to the maximum power output of the power amplifier;

[0022] When the output impedance of the power amplifier changes, the baseband output current of the power amplifier will change, and the baseband output current I o With DC supply current I dc The relationship is I dc =αI o ,in

[0023] In addition, the present invention also provides a supersurface structure, which includes the above-mentioned electromagnetic sensing system integrated into one body.

[0024] In addition, the present invention also provides a processor, characterized in that it is used to run a program, wherein the program, when being run, is used to execute: the electromagnetic sensing method for the object posture as described above.

[0025] Through the above technical solution, the electromagnetic sensing hardware architecture consists of a metasurface antenna, an active power amplifier, and a current detection circuit. The output end of the active power amplifier is connected to the input of the metasurface antenna, and the input current port of the active power amplifier is connected to the current detection circuit. The current detection circuit collects the drain current of the power amplifier in real time. The input end of the active power amplifier is connected to a signal source. By monitoring the dynamic drain current of the active power amplifier, the state of the object to be measured in space can be monitored in real time.

[0026] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0028] Figure 1 It is a module block diagram of an electromagnetic sensing system of the present invention;

[0029] Figure 2 It is a flow chart of an electromagnetic sensing method for an object posture of the present invention;

[0030] Figure 3 It is a hardware system architecture diagram of an electromagnetic sensing system of the present invention;

[0031] Figure 4 It is a hardware structure diagram of an electromagnetic sensing system of the present invention;

[0032] Figure 5 It is a super surface structure diagram of the present invention;

[0033] Figure 6 It is a transmission network principle diagram of an electromagnetic sensing system of the present invention;

[0034] FIG. 7( a ) is a schematic diagram of the real and imaginary parts of the output impedance of a power amplifier at four object positions above a metasurface structure of the present invention;

[0035] FIG7( b ) is a schematic diagram of input and output power characteristics of a power amplifier of a metasurface structure of the present invention under these four output impedances;

[0036] FIG7( c ) is a schematic diagram of the drain efficiency of a power amplifier in a power amplification metasurface of a metasurface structure of the present invention under these four output impedances;

[0037] Figure 7(d) is a schematic diagram showing that objects at different positions in a metasurface structure of the present invention have a direct impact on the performance of a power amplifier in the power amplification metasurface. DETAILED DESCRIPTION

[0038] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0039] like Figure 1 As shown, the present invention provides an electromagnetic sensing system, which includes: a metasurface antenna, which is used to radiate electromagnetic waves and capture scattered waves of the object to be measured in response to the electromagnetic waves; an active power amplifier, whose output end is connected in series with the metasurface antenna, and the output impedance of the active power amplifier can change with the scattered waves; and a current detection circuit, which is connected in series with the current input end of the active power amplifier, and is used to monitor the current change of the active power amplifier, and then respond to the perceived posture of the object to be measured.

[0040] like Figure 2 As shown, the present invention also provides an electromagnetic sensing method for an object posture, using the above-mentioned electromagnetic sensing system, the electromagnetic sensing method for an object posture comprises:

[0041] S201, the electromagnetic waves radiated by the metasurface antenna encounter an object to be measured to generate scattered waves;

[0042] S202, the scattered wave is captured by the metasurface antenna, thereby changing the output impedance of the power amplifier so as to change the DC power supply current of the power amplifier; and

[0043] S203: Determine the posture of the object to be measured according to the change of the DC power supply current.

[0044] The overall hardware architecture of the electromagnetic sensing system of the present invention is as follows: Figure 3As shown, the electromagnetic sensing hardware architecture consists of a power amplifier, an antenna, a sampling resistor and an analog-to-digital converter. The current detection circuit includes: a sampling resistor, which is cascaded with the input end of the active power amplifier; and a digital-to-analog converter, which is electrically connected to both sides of the sampling resistor, for monitoring the current change of the active power amplifier, and then realizing the perception of the posture of the object to be measured. The output end of the power amplifier is connected to the input of the antenna, the input current port of the power amplifier is connected to the sampling resistor, and the two ends of the sampling resistor are connected to the analog-to-digital converter. The analog-to-digital converter collects the drain current of the power amplifier in real time. The input end of the power amplifier is connected to a signal source. By monitoring the dynamic drain current of the power amplifier, the state of the moving object in space can be monitored in real time.

[0045] The electromagnetic metasurface antenna of the present invention is a two-dimensional or quasi-two-dimensional periodic structure antenna, which has broad application prospects in microwave and optical frequency bands. The ultra-fast electromagnetic sensing hardware platform of this solution integrates the power amplifier into the electromagnetic metasurface antenna, which has both the spatial electromagnetic capture of the metasurface and the electromagnetic induction characteristics of the power amplifier. The hardware structure of the electromagnetic sensing system proposed by the present invention is as follows: Figure 4 As shown. By monitoring the dynamic drain current of the power amplifier, the state of the moving object in space can be monitored in real time. Combined with back-end data processing, it can realize intelligent recognition and judgment of the object's movement speed, object's movement state and object type. Figure 4 It can be seen that compared with traditional radar, phased array and large-scale antenna systems, the electromagnetic perception system proposed in this project only requires active power amplifier metamaterials, without additional RF modules. And because the motion state of the object directly acts on the dynamic drain current of the power amplifier, no additional delay will be generated. The dynamic drain current of the power amplifier does not require a data sampling system with a very high sampling rate, so it can greatly reduce the delay of electromagnetic perception data processing, greatly improve the perception speed and reduce system costs.

[0046] The electromagnetic sensing system proposed in the present invention is composed of a metasurface antenna and an active power amplifier. Figure 5 Based on the connection relationship between the active power amplifier and the metasurface antenna, an equivalent transmission network model of the power amplification metasurface is established, as shown in Figure 6 As shown in the figure. When the electromagnetic waves radiated by the metasurface antenna encounter an object, the waves scattered by the object are captured by the metasurface structure, thereby changing the reflection coefficient of the metasurface structure. Since the reflection coefficient of the metasurface structure directly affects the output impedance of the power amplifier in the front-end cascade, it directly changes the power supply current and RF characteristics of the power amplifier according to the impedance boundary conditions of the power amplifier. Figure 6 It can be seen that the output reflection coefficient of the power amplifier is the input reflection coefficient of the metasurface, which can be expressed as ΓL =b L / a L , and the output impedance of the power amplifier can be obtained from its output reflection coefficient. From the load-pull theory of the power amplifier, it can be seen that the output power of the power amplifier is closely related to the impedance, and its output power is limited by the output impedance boundary. Therefore, according to the relationship between output power and impedance, it can be concluded that the output power of the power amplifier under different output impedances is:

[0047]

[0048] Where p is the ratio of the maximum output power of the power amplifier to the back-off output power and satisfies p ≥ 1, Z L and G L is the load impedance and admittance of the amplifier, P opt is the maximum or optimal output power of the power amplifier, X is the load impedance Z L The imaginary part of B is the load admittance G L The imaginary part, R opt G is the optimal output impedance corresponding to the maximum power output of the power amplifier. opt It is the optimal output admittance corresponding to the maximum power output of the power amplifier. Therefore, when the output impedance of the power amplifier changes, the baseband output current of the power amplifier will also change. According to the DC boundary conditions of the power amplifier, the output current of the power amplifier is linearly proportional to the DC of the power amplifier. dc =αI o , where α is the ratio of the DC component to the fundamental component of the power amplifier drain output current, which can be defined as

[0049]

[0050] Therefore, when the output impedance of the power amplifier changes, the DC at its drain also changes accordingly. And there is no additional time variable between the DC and impedance of the power amplifier, indicating that in theory the DC at the drain of the power amplifier responds transiently to its output impedance without the need for additional delay. Therefore, compared to other electromagnetic sensing systems, directly sensing environmental objects based on the binary boundary conditions of the power amplifier itself has an instantaneous response in theory, does not generate additional circuit delays, and does not require additional complex receiver systems and signal processing systems based on this system. In addition, since the power amplifier changes the DC signal, the corresponding monitoring circuit structure can be very simple, without the need for additional complex circuit modules such as up and down frequency conversion, low noise amplifiers, and adjustable gain amplifiers, thus greatly reducing the complexity and cost of the overall system.

[0051] When an object appears directly above the power amplification metasurface, the electromagnetic waves radiated by the power amplification metasurface encounter the object to generate scattered waves. The scattered waves are received by the metasurface array, changing the output impedance of the power amplifier and thus changing the DC supply current of the power amplifier. Based on the full-wave simulation software CST, the input impedance of the metasurface array at different spatial object positions is simulated and calculated, and the power amplifier RF and supply current are simulated in combination with the ADS software, as shown in Figure 7. The joint simulation results show that the position of the object at different positions has different degrees of influence on the input impedance of the metasurface array. The minimum resolution of the power amplification metasurface sensing the object is greater than 25mA (not a constant theoretical value, but the resolution in these four distance scenarios obtained through simulation, and this value will change with different power amplifiers, and will be further improved as the scale of the power amplification metasurface array increases), which is sufficient to be recognized by an ordinary precision analog-to-digital converter. Figure 7 (a) shows the real and imaginary parts of the output impedance of the power amplifier at four object positions above the power amplification metasurface, which shows that the position of the monitored object will change the output impedance of the power amplifier and thus change the RF performance of the power amplifier. Figure 7(b) shows the input and output power characteristics of the power amplifier in the power amplification metasurface under these four output impedances. Figure 7(c) shows the drain efficiency of the power amplifier in the power amplification metasurface under these four output impedances. Figure 7(d) shows the drain DC supply current of the power amplifier in the power amplification metasurface under these four output impedances. Figures 7(bd) show that objects at different positions have a direct impact on the performance of the power amplifier in the power amplification metasurface, which also verifies the feasibility and effectiveness of the proposed method.

[0052] In addition, the present invention also provides a processor, characterized in that it is used to run a program, wherein the program, when being run, is used to execute: the electromagnetic sensing method for the object posture as described above.

[0053] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: (steps of the method claim, sole right + subordinate right).

[0054] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0055] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0056] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0057] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0058] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0059] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0060] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0061] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0062] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0063] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. An electromagnetic sensing system, characterized in that: The electromagnetic sensing system comprises: A metasurface antenna, which is used to radiate electromagnetic waves and capture scattered waves of the electromagnetic waves from the object to be measured; an active power amplifier, the output end of which is connected in series to the metasurface antenna, and the output impedance of the active power amplifier can vary with the scattered wave; and The current detection circuit is connected in series with the current input terminal of the active power amplifier, and is used to monitor the current change of the active power amplifier, and then reflect the perceived posture of the object to be detected.

2. The electromagnetic sensing system according to claim 1, characterized in that: The current detection circuit comprises: a sampling resistor connected in cascade to an input end of the active power amplifier; and The digital-to-analog converter is electrically connected to both sides of the sampling resistor and is used to monitor the current change of the active power amplifier, thereby sensing the posture of the object to be measured.

3. The electromagnetic sensing system according to claim 1, characterized in that: The active power amplifier is integrated on the metasurface antenna.

4. A method for electromagnetically sensing an object's posture, characterized in that: Using the electromagnetic sensing system according to any one of claims 1 to 3, the electromagnetic sensing method for an object posture comprises: The electromagnetic waves radiated by the metasurface antenna generate scattered waves when encountering the object to be measured; The scattered waves are captured by the metasurface antenna, thereby changing the output impedance of the power amplifier so as to change the DC supply current of the power amplifier; and The posture of the object to be measured is determined according to the change of the DC power supply current.

5. The method for electromagnetically sensing an object's posture according to claim 4, characterized in that: The scattered wave is captured by the metasurface antenna, and then the output impedance of the power amplifier is changed so that the DC power supply current of the power amplifier is changed, which includes: The scattered waves are captured by the metasurface antenna, thereby changing the input reflection coefficient of the metasurface antenna; wherein the output impedance of the power amplifier is configured to be associated with the input reflection coefficient of the metasurface antenna; The output power of the power amplifier is configured to be associated with the output impedance, and the output power of the power amplifier is: Where P is the ratio of the maximum output power of the power amplifier to the back-off output power and satisfies p ≥ 1, Z L and G L is the load impedance and admittance of the amplifier, P opt is the maximum or optimal output power of the power amplifier, X is the load impedance Z L The imaginary part of B is the load admittance G L The imaginary part, R opt G is the optimal output impedance corresponding to the maximum power output of the power amplifier. opt It is the optimal output admittance corresponding to the maximum power output of the power amplifier; When the output impedance of the power amplifier changes, the baseband output current of the power amplifier will change, and the baseband output current I o With DC supply current I dc The relationship is I dc =αI o ,in 6. A super surface structure, characterized in that: The metasurface structure includes an integrated electromagnetic sensing system as described in any one of claims 1-3.

7. A processor, characterized in that: Used to run a program, wherein the program, when run, is used to execute: the electromagnetic perception method for the object posture as described in any one of claims 4 and 5.

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