A radio signal detection device and method based on wireless energy harvesting technology

Abstract

This invention belongs to the field of integrated circuit technology design and discloses a radio signal detection device based on wireless energy harvesting technology. It consists of two parts: a power supply and receiving end, and a sensing and transmitting end. The power supply and receiving end comprises a first antenna, a reader, and a signal source module. The sensing and transmitting end comprises a second antenna, a resonant network module, a reference generation module, a backscatter switch, a successive approximation modulation module, and a ΔΣ modulation module. This invention achieves long-distance wireless power supply and communication for an electrical signal detection system. By using successive approximation modulation and ΔΣ modulation to perform coarse and fine tuning of the detected electrical signal, it achieves higher electrical signal detection resolution and a larger electrical signal detection range. Simultaneously, the circuit structure is simple, reducing the power consumption and area of ​​the sensing and transmitting ends, thus achieving better portability and a longer wireless power supply and wireless communication distance.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit technology design, and in particular relates to a radio signal detection device and method based on wireless energy harvesting technology. Background Technology

[0002] Microsensors can detect physical parameters such as temperature, humidity, and acceleration, as well as various physiological and chemical parameters including blood glucose, blood pressure, blood oxygen, and the concentration of specific substances, through electrochemical and optical sensing methods. Microsensors convert these physical and physiological parameters into electrical signals, such as current and voltage. These signals are then detected, amplified, and transmitted to the outside world via an interface circuit—an electrical signal detection system. With the continuous development of microsensor technology, while microsensors are becoming smaller and smaller, their sensing accuracy is also increasing. This results in increasingly weak and sensitive electrical signals, placing higher demands on the electrical signal detection systems used with them.

[0003] In addition, typical sensing systems, consisting of microsensors and electrical signal detection systems, often include a large measuring and analysis instrument to achieve high-precision measurements. The instrument is connected to the sensor via cables, and the instrument itself is powered by a plug or battery, resulting in poor portability and high cost for the entire sensing system. Considering that sensing systems are gradually moving towards wearable technology, and that some sensors need to be used in hazardous environments such as high temperature and high pressure, a sensing system with wireless power supply and wireless communication capabilities is essential.

[0004] Typical electrical signal detection systems use analog-to-digital converters (ADCs) to convert analog electrical signals from sensors into digital signals and transmit them. Although this achieves good detection accuracy, ADCs have high power consumption and large area, making them unsuitable for wireless power supply systems. Summary of the Invention

[0005] The purpose of this invention is to provide a radio signal detection device and method based on wireless energy harvesting technology to solve the above-mentioned technical problems.

[0006] To solve the above-mentioned technical problems, the specific technical solution of the radio signal detection device and method based on wireless energy harvesting technology of the present invention is as follows:

[0007] A radio signal detection device based on wireless energy harvesting technology comprises two parts: a power supply and receiving end and a sensing and transmitting end. The power supply and receiving end consists of a first antenna, a reader, and a signal source module, with the first antenna and reader connected to the signal source module. The sensing and transmitting end consists of a second antenna, a resonant network module, a reference generation module, a backscatter switch, a successive approximation modulation module, and a ΔΣ modulation module. The second antenna is connected to the resonant network module, the resonant network module is connected to the reference generation module, the reference generation module is connected to the successive approximation modulation module and the ΔΣ modulation module, the successive approximation modulation module and the ΔΣ modulation module are connected, and the successive approximation modulation module and the ΔΣ modulation module are connected to the backscatter switch.

[0008] The power supply and receiving end is used to transmit a wireless signal at a specific frequency and receive the reflected signal from the sensing and transmitting end, and demodulate the data signal through a reader connected to the first antenna.

[0009] The second antenna of the sensing and transmitting end is used to collect the energy of the wireless signal transmitted by the power supply and receiving end;

[0010] The resonant network module is used to amplify the amplitude of the received wireless signal;

[0011] The reference generation module is used to generate the DC power supply voltage and reference current required by the successive approximation modulation module and the ΔΣ modulation module.

[0012] The successive approximation modulation module is used to coarsely adjust the electrical signal of the reference generation module, and then subtract the coarsely adjusted part from the detected electrical signal and input the remaining part into the ΔΣ modulation module.

[0013] The ΔΣ modulation module is used to fine-tune the electrical signal of the reference generation module;

[0014] The successive approximation modulation module and the ΔΣ modulation module output data signals carrying the detected electrical signal information and apply them to the backscatter switch;

[0015] The backscatter switch modulates the reflected signal by controlling the load of the sensing and transmitting antenna and the resonant network module by opening and closing.

[0016] Furthermore, the resonant network module in the sensing and transmitting end adopts an LC resonant circuit. If the antenna is an inductive antenna, a capacitor of corresponding size is used for resonance; if the antenna is a capacitive antenna, an inductor of corresponding size is used for resonance.

[0017] Furthermore, the reference generation module in the sensing and transmitting end includes a rectifier, a low-dropout linear regulator, and a bandgap reference. The rectifier is used to convert the differential AC voltage signal into a DC voltage signal. The DC voltage signal powers the low-dropout linear regulator and the bandgap reference. The bandgap reference is used to generate a reference voltage and reference current that are independent of process, supply voltage, and temperature. The low-dropout linear regulator uses the reference voltage of the bandgap reference as a reference and outputs a standard supply voltage that can be used to power subsequent circuits.

[0018] Furthermore, the backscatter switch is composed of two NMOS transistors, with the sources of both NMOS transistors grounded and their drains connected to the two ends of the second antenna, and the gates of the two NMOS transistors connected as the input terminals of the backscatter switch. The substrates of both NMOS transistors are grounded.

[0019] Furthermore, the successive approximation modulation module includes a binary-arranged digital-to-analog converter, an adder, an integrator, a quantizer, and a digital control module;

[0020] The digital-to-analog converter is used to generate analog electrical signals;

[0021] The adder is used to add the analog electrical signal generated by the digital-to-analog converter to the detected electrical signal;

[0022] The integrator is used to integrate the signal output by the adder.

[0023] The quantizer is used to quantize the signal output by the integrator and output it to the digital control module.

[0024] The digital control module is used to control the switching of the binary units in the digital control module.

[0025] Furthermore, the ΔΣ modulation module includes an adder, an integrator, a quantizer, a digital-to-analog converter with electrical signals in opposite directions, and a digital control module; the adder, integrator, and quantizer of the ΔΣ modulation module are multiplexed from corresponding modules in the successive approximation modulation module.

[0026] Furthermore, the successive approximation modulation module and the ΔΣ modulation module include 25 NMOS transistors connected in parallel (NM1). The reference current flows into the drain of the 25 NMOS transistors connected in parallel (NM1). The drain of NM1 is connected to its gate. The gates of NM1 and 4 NMOS transistors connected in parallel (NM2) are connected to each other, replicating the current in a 25:4 ratio. The drain of NM2 is connected to the drain of PM1. The gate of PM1 is connected to the drain of PM1 and the gate of PM2. The current flowing through NM2 is then replicated through a PMOS current mirror. The gate of NM3 is connected to the gate of NM1, and the drain is connected to a switch. The substrates and sources of all PMOS are connected to VDD, and the sources and substrates of all NMOS are grounded. PM2 and NM3 together form a digital-to-analog converter with opposite electrical signals for ΔΣ modulation. When the signal input to the digital control module is 0, the switch of NM3 is closed and the switch of PM2 is open. When the signal input to the digital control module is 1, the switch of NM3 is open and the switch of PM2 is closed.

[0027] Furthermore, in the digital-to-analog conversion module of the successive approximation modulation module, the gates of all NMOS transistors are connected to the gate of NM1, all NMOS transistors use the same unit NMOS transistor, the number m of NMOS transistors connected in parallel exhibits binary growth, and the switch on each NMOS current source represents one bit of the N-bit signal output by the successive approximation modulation module. When it is 0, the switch is open, and when it is 1, the switch is closed. The successive approximation modulation of the detected electrical signal from the high bit to the low bit is realized through the digital logic in the digital control module of the successive approximation modulation module.

[0028] Furthermore, the power supply and receiving end consists of a radio frequency signal source, a power amplifier, a duplexer, a first antenna, and a demodulation circuit;

[0029] The radio frequency signal source is used to transmit a radio frequency signal with a frequency of F1 to the power amplifier;

[0030] The power amplifier is used to amplify the radio frequency signal and transmit it to the transmitter of the duplexer;

[0031] The duplexer has a built-in filter from the transmitter to the antenna to filter the signal; then the signal is transmitted outward through the first antenna at the antenna end of the duplexer.

[0032] The duplexer is used to receive reflected signals from both the sensing and transmitting ends, resulting in a data signal with a frequency of F2.

[0033] The demodulation circuit is used to demodulate and analyze the data signals received by the duplexer.

[0034] This invention also discloses a method for detecting radio signals based on wireless energy harvesting technology, comprising the following steps:

[0035] The reader and signal source module in the power supply and receiver transmit a wireless signal of a specific frequency through the first antenna. The second antenna in the sensing and transmitting end performs wireless energy harvesting at this signal frequency. The amplitude of the signal is amplified through the resonant network at this frequency. Then, this differential AC signal is transmitted to the reference generation module. The reference generation module generates the DC supply voltage and reference current required by the successive approximation modulation module and the ΔΣ modulation module. The detected electrical signal is first transmitted to the successive approximation modulation module for coarse adjustment. Then, the coarse adjustment part is subtracted from the detected electrical signal, and the remaining part is transmitted to the ΔΣ modulation module for fine adjustment. The two modulation modules transmit data signals carrying the detected electrical signal information and apply them to the backscatter switch. The data signal controls the opening and closing of the backscatter switch to control the load of the sensing and transmitting end antenna and the resonant network, thereby modulating the reflected signal. The modulated reflected signal is received by the first antenna of the power supply and receiver end, and the data signal is demodulated by the reader connected to the first antenna.

[0036] Successive approximation modulation includes: adding the analog electrical signal generated by the digital-to-analog converter (DAC) to the detected electrical signal via an adder, integrating the result, and then quantizing it via a quantizer. The output of the quantizer is connected to a digital control module (DC module), which controls the switching of the binary units in the DAC module. The DAC outputs an N-bit digital signal. The DC module starts judging from the most significant bit of this digital signal. The most significant bit occupies 1 / 2 of the full-scale analog output of the DAC, the second most significant bit occupies 1 / (2^1) of the full-scale analog output of the DAC, the third most significant bit occupies 1 / (2^2) of the full-scale analog output of the DAC, and so on. By judging whether each bit is 0 or 1 from the most significant bit onwards, the successive approximation of the detected electrical signal is achieved. Finally, this N-bit digital signal is fed into the backscatter switch.

[0037] ΔΣ modulation includes: a digital control module controls a digital-to-analog converter (DAC) with an opposite-direction electrical signal to output either an inverted or forward electrical signal by outputting 0 or 1. The electrical signal output by the DAC is added to the detected electrical signal after subtracting the coarse-tuning portion of the successive approximation modulation, and then integrated by an integrator. The result is then quantized by a quantizer. The quantization result is fed back to the DAC with the opposite-direction electrical signal by the digital control module, modifying its output so that the average value of the output signal of the DAC with the opposite-direction electrical signal approximates the remaining portion after subtracting the coarse-tuning portion of the successive approximation modulation from the detected electrical signal. This remaining portion, which is the portion fine-tuned by the ΔΣ modulation module, is converted into a bit stream of 0s and 1s, i.e., a square wave signal. The duty cycle of this square wave signal reflects the size of the fine-tuning portion. Finally, this square wave signal is input into the backscatter switch.

[0038] The radio signal detection device and method based on wireless energy harvesting technology of the present invention have the following advantages: The present invention achieves long-distance wireless power supply to the sensor and transmitter through dual antennas, achieves long-distance wireless signal transmission through backscattering technology, coarsely adjusts the detected electrical signal through successive approximation modulation, and finely adjusts the remaining part of the detected electrical signal after subtracting the coarse adjustment through ΔΣ modulation. This achieves higher electrical signal detection resolution and a larger electrical signal detection range. Simultaneously, the circuit structure is simple, avoiding the use of complex and high-power, large-area modules such as analog-to-digital converters (ADCs), reducing the power consumption and area of ​​the sensor and transmitter, thus achieving better portability and longer wireless power supply and wireless signal transmission distances. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall architecture of the radio signal detection device based on wireless energy harvesting technology of the present invention;

[0040] Figure 2 This is a block diagram of the successive approximation modulation and ΔΣ modulation modules in this invention;

[0041] Figure 3 This is a circuit diagram of the digital-to-analog converter in the successive approximation modulation and ΔΣ modulation modules of this invention;

[0042] Figure 4 This is a block diagram of the power supply and receiving end modules in this invention. Detailed Implementation

[0043] To better understand the purpose, structure, and function of this invention, the following detailed description of a radio signal detection device and method based on wireless energy harvesting technology is provided in conjunction with the accompanying drawings.

[0044] like Figure 1As shown, a radio signal detection system based on wireless energy harvesting technology consists of two parts: a power supply and receiving end, and a sensing and transmitting end. The power supply and receiving end comprises a first antenna and a reader / signal source module; the first antenna and the reader / signal source module are connected. The sensing and transmitting end comprises an antenna, a resonant network module, a reference generation module, a backscatter switch, a successive approximation modulation module, and a ΔΣ modulation module. The second antenna is connected to the resonant network module, which is connected to the reference generation module. The reference generation module is connected to both the successive approximation modulation module and the ΔΣ modulation module. The successive approximation modulation module and the ΔΣ modulation module are connected together, and the successive approximation modulation module and the ΔΣ modulation module are connected to the backscatter switch. During normal operation, the reader / signal source module in the power supply and receiving end transmits a wireless signal of a specific frequency through the first antenna. The second antenna in the sensing and transmitting end harvests wireless energy at this signal frequency. The resonant network module at this frequency amplifies the amplitude of the signal, and then this differential AC signal is transmitted to the reference generation module. The reference generation module generates the DC supply voltage and reference current required by the successive approximation modulation module and the ΔΣ modulation module. The detected electrical signal is first fed into the successive approximation modulation module for coarse adjustment. Then, the coarse-adjusted part is subtracted from the detected electrical signal, and the remaining part is fed into the ΔΣ modulation module for fine adjustment. The two modulation modules output data signals carrying the information of the detected electrical signal, which are applied to the backscatter switch. The data signals control the opening and closing of the backscatter switch to control the load of the sensing and transmitting antenna and the resonant network module, thereby modulating the reflected signal. The modulated reflected signal is received by the first antenna of the power supply and receiving end, and the data signal is demodulated by the reader connected to the first antenna.

[0045] The resonant network module in the sensing and transmitting end can use an LC resonant circuit. If the antenna is an inductive antenna, a capacitor of the corresponding size is used for resonance; if the antenna is a capacitive antenna, an inductor of the corresponding size is used for resonance.

[0046] The reference generation module in the sensing and transmitting end may include a rectifier, a low-dropout linear regulator, and a bandgap reference. The rectifier is used to convert the differential AC voltage signal into a DC voltage signal, which then powers the low-dropout linear regulator and the bandgap reference. The bandgap reference generates a reference voltage and reference current that are independent of process, supply voltage, and temperature. The low-dropout linear regulator uses the reference voltage of the bandgap reference as a reference and outputs a standard supply voltage that can be used to power subsequent circuits.

[0047] The backscatter switch in the sensing and transmitting end can be composed of two NMOS transistors. The sources of the two NMOS transistors are grounded, and their drains are connected to the two ends of the second antenna. The gates of the two NMOS transistors are connected as the input terminals of the backscatter switch, and the substrates of the two NMOS transistors are grounded.

[0048] like Figure 2 This illustration shows an embodiment of the successive approximation modulation module and the ΔΣ modulation module in the sensing and transmitting ends of a radio signal detection system based on wireless energy harvesting technology according to the present invention. Since the only difference between the two is the digital-to-analog converter and the digital control module, the integrator, adder, and quantizer are multiplexed, and therefore described together here. Both the successive approximation modulation module and the ΔΣ modulation module can be composed of an integrator, an adder, a quantizer, a digital-to-analog converter, and a digital control module. The detected electrical signal and the analog signal output from the digital-to-analog converter (DAC) are fed into an adder, where they are added together. The result of the adder is then fed into an integrator, where integration is performed. Here, we use a comparator as a quantizer. The result of the integrator is input to the inverting input of the comparator, and a reference voltage is connected to the non-inverting input of the comparator. Through the comparator, we can output the quantization result. This quantization result is then fed into the digital control module, which can control the switches in the DAC, changing the analog signal output of the DAC. Through this negative feedback, in successive approximation modulation, the analog output of the DAC is made closer to the detected electrical signal. In ΔΣ modulation, the analog output of the DAC is made closer to the remaining part of the detected electrical signal after subtracting the coarse adjustment part of the successive approximation modulation.

[0049] Specifically, the successive approximation modulation module in the sensing and transmitting end can include a binary-arranged digital-to-analog converter (DAC), adders, integrators, quantizers, and a digital control module. The analog electrical signal generated by the DAC is added to the detected electrical signal via the adder, then integrated by the integrator, and finally quantized by the quantizer. The output of the quantizer is connected to the digital control module, which controls the switching of a series of binary units within the DAC module. The DAC outputs an N-bit digital signal. The digital control module starts judging from the most significant bit of this signal. The most significant bit occupies half of the full-scale analog output of the DAC, the second most significant bit occupies 1 / (2^1), the third most significant bit occupies 1 / (2^2), and so on. By judging each bit sequentially from the most significant bit to the next, the successive approximation of the detected electrical signal is achieved. Finally, this N-bit digital signal is fed into the backscatter switch.

[0050] The ΔΣ modulation module at the sensing and transmitting end includes an adder, an integrator, a quantizer, a digital-to-analog converter (DAC) with an electrical signal in the opposite direction, and a digital control module. The adder, integrator, and quantizer can be multiplexed from corresponding modules in the successive approximation modulation module. The digital control module controls a digital-to-analog converter (DAC) with an opposite electrical signal to output either a reversed or forward electrical signal by outputting 0 or 1. The DAC output signal is added to the detected signal after subtracting the successive approximation modulation coarse adjustment portion, and then integrated by an integrator. The result is then quantized by a quantizer. The quantization result is fed back to the DAC with the opposite electrical signal through the digital control module, modifying its output so that the average value of the DAC output signal approximates the detected signal after subtracting the successive approximation modulation coarse adjustment portion. This remaining portion, which is the fine-tuned portion using the ΔΣ modulation module, is converted into a bit stream of 0s and 1s, i.e., a square wave signal. The duty cycle of this square wave signal reflects the magnitude of the fine-tuning portion. Finally, this square wave signal is fed into the backscatter switch.

[0051] like Figure 3This diagram illustrates an embodiment of a digital-to-analog converter (DAC) circuit in the successive approximation modulation module and the ΔΣ modulation module of a radio signal detection system based on wireless energy harvesting technology, according to the present invention. A reference current flows into the drain of NM1, which consists of 25 NMOS transistors connected in parallel. The drain and gate of NM1 are connected. The gates of NM1 and NM2, consisting of 4 NMOS transistors connected in parallel, are connected, thus replicating the current in a 25:4 ratio. Then, the drain of NM2 is connected to the drain of PM1, and the gate of PM1 is connected to the drain of PM1 and the gate of PM2. The current flowing through NM2 is then replicated through a PMOS current mirror. The gate of NM3 is connected to the gate of NM1, and its drain is connected to a switch. Thus, PM2 and NM3 together constitute a ΔΣ modulation DAC with oppositely oriented electrical signals. When the signal input to the digital control module is 0, the switch of NM3 is closed, and the switch of PM2 is open. When the signal input to the digital control module is 1, the switch of NM3 is open, and the switch of PM2 is closed. In the digital-to-analog converter module used for successive approximation modulation, the gates of all NMOS transistors are connected to the gate of NM1. All NMOS transistors use the same unit NMOS transistors, and the number m of them connected in parallel increases in binary order. NM4 is connected in parallel with 1 unit NMOS transistor, NM5 is connected in parallel with 2 unit NMOS transistors, NM6 is connected in parallel with 4 unit NMOS transistors, and so on. The switch on each NMOS current source represents one bit of the N-bit signal output by the successive approximation modulation module. When it is 0, the switch is open, and when it is 1, the switch is closed. The successive approximation modulation of the detected electrical signal from the high bit (NM10) to the low bit (NM4) is realized by the digital logic in the digital control module. Figure 3 All PMOS substrates are connected to VDD, and all sources are connected to VDD. All NMOS sources are grounded, and all substrates are grounded.

[0052] like Figure 4 This illustration shows an embodiment of the power supply and receiving end in a radio signal detection system based on wireless energy harvesting technology according to the present invention. The power supply and receiving end can consist of a radio frequency (RF) signal source, a power amplifier, a duplexer, a first antenna, and a demodulation circuit. The RF signal source transmits an RF signal with a frequency of F1 to the power amplifier. After amplification, the RF signal is transmitted to the transmitting end of the duplexer. The signal is filtered by a built-in filter from the transmitting end to the antenna end of the duplexer, and then transmitted outward through the first antenna at the antenna end of the duplexer. After receiving the reflected signal from the sensing and transmitting ends, the reflected signal passes through the filter inside the duplexer from the antenna end to the receiving end, resulting in a data signal with a frequency of F2. This signal can be transmitted to a reader, including a demodulation circuit, for demodulation and analysis.

[0053] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A radio signal detection device based on wireless energy harvesting technology, comprising two parts: a power supply and receiving end and a sensing and transmitting end, characterized in that, The power supply and receiving end consists of a first antenna, a reader, and a signal source module, with the first antenna connected to the reader and the signal source module. The sensing and transmitting end consists of a second antenna, a resonant network module, a reference generation module, a backscatter switch, a successive approximation modulation module, and a ΔΣ modulation module. The second antenna is connected to the resonant network module, the resonant network module is connected to the reference generation module, the reference generation module is connected to the successive approximation modulation module and the ΔΣ modulation module, the successive approximation modulation module and the ΔΣ modulation module are connected, and the successive approximation modulation module and the ΔΣ modulation module are connected to the backscatter switch. The power supply and receiving end is used to transmit a wireless signal at a specific frequency and receive the reflected signal from the sensing and transmitting end, and demodulate the data signal through a reader connected to the first antenna. The second antenna of the sensing and transmitting end is used to collect the energy of the wireless signal transmitted by the power supply and receiving end; The resonant network module is used to amplify the amplitude of the received wireless signal; The reference generation module is used to generate the DC power supply voltage and reference current required by the successive approximation modulation module and the ΔΣ modulation module. The successive approximation modulation module is used to coarsely adjust the electrical signal of the reference generation module, and then subtract the coarsely adjusted part from the detected electrical signal and input the remaining part into the ΔΣ modulation module. The ΔΣ modulation module is used to fine-tune the electrical signal of the reference generation module; The successive approximation modulation module and the ΔΣ modulation module output data signals carrying the detected electrical signal information and apply them to the backscatter switch; The backscatter switch controls the load of the sensing and transmitting antenna and the resonant network module by opening and closing, thereby modulating the reflected signal; The successive approximation modulation module includes a binary-arranged digital-to-analog converter, adder, integrator, quantizer, and digital control module. The digital-to-analog converter is used to generate analog electrical signals; The adder is used to add the analog electrical signal generated by the digital-to-analog converter to the detected electrical signal; The integrator is used to integrate the signal output by the adder. The quantizer is used to quantize the signal output by the integrator and output it to the digital control module. The digital control module is used to control the switching of the binary units in the digital-to-analog converter; The ΔΣ modulation module includes an adder, an integrator, a quantizer, a digital-to-analog converter with electrical signals in opposite directions, and a digital control module; the adder, integrator, and quantizer of the ΔΣ modulation module are multiplexed from corresponding modules in the successive approximation modulation module; The successive approximation modulation module and the ΔΣ modulation module include 25 NMOS transistors connected in parallel (NM1). The reference current flows into the drain of the 25 NMOS transistors in parallel (NM1). The drain of NM1 is connected to its gate. The gates of NM1 and 4 NMOS transistors connected in parallel (NM2) are connected, replicating the current in a 25:4 ratio. The drain of NM2 is connected to the drain of PM1. The gate of PM1 is connected to the drain of PM1 and the gate of PM2. The current flowing through NM2 is then replicated through a PMOS current mirror. The gate of PMOS is connected to the gate of NM1, and the drain is connected to a switch. The substrates and sources of all PMOS are connected to VDD. The sources and substrates of all NMOS are grounded. PM2 and NM3 together form a digital-to-analog converter with opposite electrical signals for ΔΣ modulation. When the signal input to the digital control module is 0, the switch of NM3 is closed and the switch of PM2 is open. When the signal input to the digital control module is 1, the switch of NM3 is open and the switch of PM2 is closed. In the digital-to-analog conversion module of the successive approximation modulation module, the gates of all NMOS transistors are connected to the gate of NM1. All NMOS transistors use the same unit NMOS transistor. The number m of NMOS transistors connected in parallel increases in binary order. The switch on each NMOS current source represents one bit of the N-bit signal output by the successive approximation modulation module. When the value is 0, the switch is open, and when the value is 1, the switch is closed. The successive approximation modulation of the detected electrical signal from the high bit to the low bit is achieved through the digital logic in the digital control module of the successive approximation modulation module.

2. The radio signal detection device based on wireless energy harvesting technology according to claim 1, characterized in that, The resonant network module in the sensing and transmitting end adopts an LC resonant circuit. If the antenna is an inductive antenna, a capacitor of corresponding size is used for resonance; if the antenna is a capacitive antenna, an inductor of corresponding size is used for resonance.

3. The radio signal detection device based on wireless energy harvesting technology according to claim 1, characterized in that, The reference generation module in the sensing and transmitting end includes a rectifier, a low-dropout linear regulator, and a bandgap reference. The rectifier is used to convert differential AC voltage signals into DC voltage signals. The DC voltage signals power the low-dropout linear regulator and the bandgap reference. The bandgap reference is used to generate a reference voltage and a reference current that are independent of process, supply voltage, and temperature. The low-dropout linear regulator uses the reference voltage of the bandgap reference as a reference and outputs a standard supply voltage that can be used to power subsequent circuits.

4. The radio signal detection device based on wireless energy harvesting technology according to claim 1, characterized in that, The backscatter switch is composed of two NMOS transistors. The sources of both NMOS transistors are grounded, and their drains are connected to the two ends of the second antenna. The gates of the two NMOS transistors are connected to serve as the input terminals of the backscatter switch. The substrates of both NMOS transistors are grounded.

5. The radio signal detection device based on wireless energy harvesting technology according to claim 1, characterized in that, The power supply and receiving end consists of a radio frequency signal source, a power amplifier, a duplexer, a first antenna, and a demodulation circuit. The radio frequency signal source is used to transmit a radio frequency signal with a frequency of F1 to the power amplifier; The power amplifier is used to amplify the radio frequency signal and transmit it to the transmitter of the duplexer; The duplexer has a built-in filter from the transmitter to the antenna to filter the signal; then the signal is transmitted outward through the first antenna at the antenna end of the duplexer. The duplexer is used to receive reflected signals from both the sensing and transmitting ends, resulting in a data signal with a frequency of F2. The demodulation circuit is used to demodulate and analyze the data signals received by the duplexer.

6. A method for detecting radio signals using a radio signal detection device based on wireless energy harvesting technology as described in any one of claims 1-5, characterized in that, Includes the following steps: The reader and signal source module in the power supply and receiver transmit a wireless signal of a specific frequency through the first antenna. The second antenna in the sensing and transmitting end performs wireless energy harvesting at this signal frequency. The amplitude of the signal is amplified through a resonant network at this frequency. Then, this amplified AC signal is transmitted to the reference generation module. The reference generation module generates the DC supply voltage and reference current required by the successive approximation modulation module and the ΔΣ modulation module. The detected electrical signal is first transmitted to the successive approximation modulation module for coarse adjustment. Then, the coarse adjustment part is subtracted from the detected electrical signal, and the remaining part is transmitted to the ΔΣ modulation module for fine adjustment. The two modulation modules transmit data signals carrying the information of the detected electrical signal, which are applied to the backscatter switch. The data signal controls the opening and closing of the backscatter switch to control the load of the sensing and transmitting end antenna and the resonant network, thereby modulating the reflected signal. The modulated reflected signal is received by the first antenna of the power supply and receiver end, and the data signal is demodulated by the reader connected to the first antenna. Successive approximation modulation includes: adding the analog electrical signal generated by the digital-to-analog converter (DAC) to the detected electrical signal via an adder, integrating the result, and then quantizing it via a quantizer. The output of the quantizer is connected to a digital control module (DC module), which controls the switching of the binary units in the DAC module. The DAC outputs an N-bit digital signal. The DC module starts judging from the most significant bit of this digital signal. The most significant bit occupies 1 / 2 of the full-scale analog output of the DAC, the second most significant bit occupies 1 / (2^2) of the full-scale analog output of the DAC, the third most significant bit occupies 1 / (2^3) of the full-scale analog output of the DAC, and so on. By judging whether each bit is 0 or 1 from the most significant bit onwards, the successive approximation of the detected electrical signal is achieved. Finally, this N-bit digital signal is fed into the backscatter switch. ΔΣ modulation includes: a digital control module controls a digital-to-analog converter (DAC) with an opposite-direction electrical signal to output either an inverted or forward electrical signal by outputting 0 or 1. The electrical signal output by the DAC is added to the detected electrical signal after subtracting the coarse-tuning portion of the successive approximation modulation, and then integrated by an integrator. The result is then quantized by a quantizer. The quantization result is fed back to the DAC with the opposite-direction electrical signal by the digital control module, modifying its output so that the average value of the output signal of the DAC with the opposite-direction electrical signal approximates the remaining portion after subtracting the coarse-tuning portion of the successive approximation modulation from the detected electrical signal. This remaining portion, which is the portion fine-tuned by the ΔΣ modulation module, is converted into a bit stream of 0s and 1s, i.e., a square wave signal. The duty cycle of this square wave signal reflects the size of the fine-tuning portion. Finally, this square wave signal is input into the backscatter switch.

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