A battery-free, ultra-low power consumption, radio frequency energy-harvesting, shared antenna tag device

Abstract

The present invention discloses a battery-free, ultra-low-power radio frequency energy-harvesting, shared-antenna tag device, which belongs to low-power Internet of Things communication technology. The tag-end device's initial state defaults to a standby state. When the tag-end device operates in the standby state, a control unit controls a switching unit to connect the antenna and the wake-up unit. When the tag-end device operates in the receiving state, the control unit controls the switching unit to connect the antenna and the downlink signal demodulation unit. When the tag-end device operates in the backscattering state, the control unit controls the switching unit to connect the antenna and the backscattering signal modulation unit. The control unit processes the collected information from the sensor into a modulated signal. The backscattering signal modulation unit receives the carrier from the antenna and the modulation signal from the control unit, modulates them, generates a modulated signal, and outputs it to the antenna to complete backscattering. The present invention adopts a radio frequency energy-harvesting and communication transceiver shared antenna mode, and realizes a low-power, battery-free design.

Description

Technical Field

[0001] The present invention relates to wireless communication technology, and in particular to low-power Internet of Things communication technology. Background Art

[0002] With the development of the Internet of Things (IoT), sensor nodes in large-scale, low-cost wireless sensor networks have become a research hotspot. Existing wireless sensor networks are mostly battery-powered and communicate wirelessly over short distances. However, in many applications, regular battery replacement by maintenance personnel at the nodes is difficult and costly. Providing power, routine maintenance, and wireless communication for these numerous miniaturized devices is becoming increasingly challenging.

[0003] Wireless communication systems based on backscatter technology are also attracting widespread attention. One benefit of this communication system is the ability to implement passive tags, making it a key technology for the future smart Internet of Things. Backscatter wireless communication systems consist of a reader / writer and a tag. The tag transmits locally stored device IDs to the reader / writer via radio frequency signals and can also transmit environmental information collected by local sensors.

[0004] The tag modulates the signal by utilizing the different reflection coefficients obtained when the antenna is connected to different loads. This is achieved by changing the antenna's impedance. When the antenna is terminated with different impedances, the reflected signal strength and phase change. This change can be exploited to achieve signal modulation, enabling signal transmission and reception on the same antenna. Backscatter communication is often based on binary amplitude shift keying (2ASK), which transmits binary data by varying the carrier amplitude. The carrier amplitude varies with the binary signal.

[0005] Using a tag based on backscatter as a sensor node can eliminate the need for batteries and is a solution for sensor nodes in wireless sensor networks that is easy to maintain and has good environmental compatibility. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a low-power, shared-antenna and battery-free tag-end device suitable for use as a sensor node based on backscatter.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: an antenna, a power splitter, an energy acquisition unit, an energy management unit, a switching unit, a wake-up unit, a sensor, a communication unit and a control unit; the communication unit includes a backscatter signal modulation unit and a downlink signal demodulation unit;

[0008] The antenna is connected to the input end of the energy acquisition unit and the switching unit through a power splitter; the switching unit is used to switch the connection between the input end of the wake-up unit, the backscattered signal modulation unit, and the input end of the downlink signal demodulation unit; the control unit is respectively connected to the output end of the wake-up unit, the output end of the sensor, the modulation signal input end of the backscattered signal modulation unit of the communication unit, and the output end of the downlink signal demodulation unit; the energy management unit supplies power to the communication unit, the wake-up unit, the sensor, and the control unit;

[0009] The initial state of the tag-end device defaults to the waiting state. When the tag-end device is working in the waiting state, the energy management unit only supplies power to the wake-up unit and the control unit. The control unit controls the switching unit to connect the antenna and the wake-up unit, and the control unit is in the dormant state. When the wake-up unit receives the wake-up signal from the antenna, the wake-up unit sends a pulse signal to the control unit, and the control unit controls the tag-end device to enter the receiving state.

[0010] When the tag-end device is operating in the receiving state, the energy management unit supplies power to the control unit and the downlink signal demodulation unit. The control unit controls the switching unit to connect the antenna and the downlink signal demodulation unit, and the control unit operates in a low-power operation state. The downlink signal demodulation unit demodulates the radio frequency signal from the antenna and outputs the demodulated signal to the control unit for decoding. After the control unit completes the decoding, the control unit controls the tag-end device to enter the backscattering state.

[0011] When the tag-end device is working in the backscattering state, the energy management unit supplies power to the control unit, the sensor and the backscattering signal modulation unit. The control unit controls the switching unit to connect the antenna and the backscattering signal modulation unit. The sensor transmits the collected information to the control unit. The control unit processes the collected information into a modulated signal and outputs it to the modulation signal input end of the backscattering signal modulation unit. The backscattering signal modulation unit receives the carrier from the antenna and the modulation signal from the control unit, modulates them, generates a modulated signal, and outputs it to the antenna to complete backscattering. After the backscattering is completed, the control unit controls the tag-end device to enter the wake-up state.

[0012] Today's low-power sensor technologies effectively reduce the power consumption of sensor nodes in short-range wireless communications. This makes it feasible to collect ambient energy around sensor nodes and convert it into electrical energy to power the nodes. Passive wireless communication systems use radio frequency signals in the environment as an energy source, leveraging environmental backscatter technology to achieve wireless communication between passive devices. This eliminates the sensor nodes' reliance on batteries. This power solution, which does not require external power input, effectively reduces sensor operation and maintenance costs and extends the lifespan of sensor nodes.

[0013] Furthermore, for the tag end device of the 2ASK modulation signal, in order to improve the high sensitivity reception of the tag end device and avoid the backscatter self-interference problem, the present invention also provides an active frequency shifting backscatter 2ASK modulation unit as a backscatter signal modulation unit.

[0014] In addition to outputting a 2ASK modulated signal, the control unit is also used to output a frequency-shifted signal. The control unit includes a first control signal output terminal and a second control signal output terminal. The control unit outputs the 2ASK modulated signal through the first control signal output terminal and outputs the frequency-shifted signal through the second control signal output terminal.

[0015] The specific structure of the backscatter signal modulation unit is as follows: it includes a signal directional transmission isolation module and a switch amplification modulation circuit; the antenna is connected to the signal directional transmission isolation module through a power divider; the switch amplification modulation circuit includes a circuit switching unit, a carrier signal input terminal, a modulation signal input terminal, a modulated signal input terminal, a frequency shift signal input terminal, a non-output reflection signal terminal, a filtering and amplification unit, and a backscatter signal output terminal;

[0016] The 2ASK modulation signal is output to the modulation signal input terminal of the line switching unit through the first control signal output terminal of the control unit, and the frequency shift signal is output to the frequency shift signal input terminal of the line switching unit through the second control signal output terminal of the control unit;

[0017] The antenna is connected to the carrier signal input terminal and the backscatter signal output terminal through the signal directional transmission isolation module, the modulation signal input terminal is connected to the modulated signal input terminal, the frequency shift signal input terminal is connected to the input terminal of the filter amplifier unit, and the output terminal of the filter amplifier unit is connected to the backscatter signal output terminal; the line switching unit controls the carrier signal input terminal to be connected to the modulation signal input terminal or to the no-output reflection signal terminal, and controls the modulated signal input terminal to be connected to the frequency shift signal input terminal or to the no-output reflection signal terminal.

[0018] The working principle of the backscatter signal modulation unit is:

[0019] When the 2ASK modulation signal is 1, the line switching unit controls the carrier signal input terminal to be connected to the modulation signal input terminal, and controls the modulated signal input terminal to be connected to the frequency shift signal input terminal. The carrier from the antenna and the 2ASK modulation signal from the control unit are modulated to generate a 2ASK modulated signal to the modulated signal input terminal. The 2ASK modulated signal is frequency-shifted by the frequency shift signal from the control unit, and then passes through the filtering and amplifying unit to form a frequency-shifted backscattered 2ASK modulated signal to the backscattered signal output terminal, and finally radiated into space through the antenna.

[0020] When the 2ASK modulation signal is 0, the line switching unit controls the carrier signal input terminal and the modulated signal input terminal to be connected to the no-output reflected signal terminal.

[0021] The beneficial effects of the present invention are that a battery-free design is realized, and the radio frequency energy acquisition and communication share the same antenna, and ultra-low power consumption operation of the device is achieved through a high-sensitivity wake-up unit. It has the advantages of easy maintenance, good environmental compatibility, long service life, and stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a block diagram of the module composition of the tag device in the embodiment;

[0023] Figure 2 This is a flowchart of the energy management unit workflow in an embodiment;

[0024] Figure 3 The embodiment wakes up the unit to receive the signal waveform;

[0025] Figure 4 This is the signal waveform after envelope detection of the wake-up unit in the embodiment;

[0026] Figure 5 A pulse signal generated by the wake-up device of the embodiment;

[0027] Figure 6 Schematic diagram of an active frequency shifting Backscatter 2ASK modulation unit according to an embodiment;

[0028] Figure 7 Backscatter modulation signal waveform of the communication unit of the embodiment;

[0029] Figure 8 This figure is a spectrum diagram of the backscattered modulation signal of the communication unit of the embodiment. Specific implementation methods

[0030] The ultra-low-power RF energy tag device described in the embodiment is shown in the figure and includes an antenna, an energy acquisition unit, a switching unit, an energy management unit, a wake-up unit, a sensor, a communication unit, and a control unit. The communication unit includes a backscatter signal modulation unit and a downlink signal demodulation unit.

[0031] The switching unit is used to switch connections between the wake-up unit input, the backscatter signal modulation unit, and the downlink signal demodulation unit input. The switching unit consists of single-pole double-throw switch 1 and single-pole double-throw switch 2. Single-pole double-throw switch 1 has three ports: a fixed port (RFc1) and two moving ports (RFs11 and RFs12). Single-pole double-throw switch 2 has three ports: a moving port (RFc2) and two fixed ports (RFs21 and RFs22).

[0032] The antenna is connected to the RFc1 end of the single-pole double-throw switch 1 through a power splitter, the RFs12 end is connected to the backscatter signal modulation unit of the communication unit, and the RFs11 end is connected to the RFc2 end of the single-pole double-throw switch 2; of the two fixed ports of the single-pole double-throw switch 2, the RFs22 end is connected to the input end of the downlink signal demodulation unit, and the RFs21 end is connected to the input end of the wake-up unit.

[0033] The control unit is respectively connected to the output end of the wake-up unit, the output end of the sensor, the modulation signal input end of the backscatter signal modulation unit of the communication unit, and the output end of the downlink signal demodulation unit; the energy management unit supplies power to the communication unit, the wake-up unit, the sensor and the control unit.

[0034] The energy harvesting unit includes a matching network and a rectifier-boost circuit. When the rectifier-boost circuit is matched with the antenna, the reflection of the incident power of the antenna RF signal will be reduced, thereby reducing losses and making better use of RF energy. The rectifier-boost circuit can convert AC RF signals into DC power and increase the voltage. Since the RF energy harvesting module can only collect very limited energy from ambient electromagnetic waves, it is generally impossible to make ordinary diodes conduct. Therefore, a Schottky diode with a lower voltage threshold and lower junction capacitance than a PN diode is selected in the rectifier circuit of the device. This allows the rectifier circuit to have a larger frequency operating range and can operate effectively at low power.

[0035] The energy management unit includes a power management chip and a supercapacitor. The power from the energy acquisition unit is boosted and output by the power management chip. When the voltage reaches the set value, it is input into the supercapacitor for energy storage. When the device is working in different states, the energy management unit supplies different power to different parts of the device. Figure 2 This is a flowchart of the energy management unit's workflow; the device's initial state defaults to the waiting state, at which point the energy management unit only supplies power to the wake-up unit and the control unit MCU, and the MCU is in sleep mode; when the device's wake-up unit receives a wake-up signal from the antenna, the wake-up unit sends a pulse signal to the MCU, and the MCU enters a low-power operation state. The MCU controls the switching of the single-pole double-throw switch, and the device enters a receiving state. The energy management unit supplies power to the MCU and the communication unit's downlink signal receiving channel; when the device receives a broadcast signal, the MCU controls the switching of the single-pole double-throw switch, and the device enters a backscattering state. The energy management unit supplies power to the sensor, MCU, and the communication unit's backscattering channel.

[0036] The wake-up unit consists of an envelope detector and a wake-up device. The wake-up device, operating in monitoring mode, only has an amplifier and clock generator active. Upon detecting a low-frequency carrier signal between 15 and 150 kHz, it outputs a pulse signal, which is sent to the MCU for wake-up. Because the required wake-up signal frequency is low, the wake-up device boasts ultra-low power consumption in the nW range. However, due to the shared antenna design, the antenna operates at a higher frequency and cannot receive low-frequency carrier signals. Therefore, envelope detection is added before the wake-up device. When the antenna receives an ASK signal, the signal undergoes envelope detection, generating a low-frequency carrier signal that wakes the wake-up device.

[0037] The communication unit includes a backscatter modulated signal transmission channel and a downlink signal receiving channel. The control unit's MCU transmits sensor information through the backscatter modulated signal transmission channel and antenna. The downlink signal receiving channel includes an amplifier, matching, envelope detection, and comparator, and is used to receive commands from other devices.

[0038] The RF signal passes through the antenna and then the power divider, all the way into the energy acquisition unit, and then through the matching network into the rectifier and boost circuit, and is converted into usable DC power and then enters the energy management unit, thereby completing the RF energy acquisition and supplying power to the active devices in the device.

[0039] The control unit provides control signals to both the single-pole double-throw switch 1 and the single-pole double-throw switch 2, thereby switching the working states of the devices.

[0040] The initial state of the tag-end device defaults to the waiting state. When the tag-end device is working in the waiting state, the energy management unit only supplies power to the wake-up unit and the control unit. The control unit controls the switching unit to connect the antenna and the wake-up unit, and the control unit is in the dormant state. When the wake-up unit receives the wake-up signal from the antenna, the wake-up unit sends a pulse signal to the control unit, and the control unit controls the tag-end device to enter the receiving state.

[0041] When the tag-end device is operating in the receiving state, the energy management unit supplies power to the control unit and the downlink signal demodulation unit. The control unit controls the switching unit to connect the antenna and the downlink signal demodulation unit, that is, the antenna is connected to the receiving channel, and the control unit operates in a low-power operation state; the downlink signal demodulation unit demodulates the radio frequency signal from the antenna and outputs the demodulated signal to the control unit for decoding; after the control unit completes the decoding, the control unit controls the tag-end device to enter the backscattering state;

[0042] When the tag-end device is working in the backscattering state, the energy management unit supplies power to the control unit, the sensor and the backscattering signal modulation unit. The control unit controls the switching unit to connect the antenna and the backscattering signal modulation unit, that is, the antenna is connected to the reverse dispersion transmission channel; the sensor transmits the collected information to the control unit, the control unit processes the collected information into a modulated signal and outputs it to the modulation signal input end of the backscattering signal modulation unit, the backscattering signal modulation unit receives the carrier from the antenna and the modulation signal from the control unit, modulates them to generate a modulated signal and outputs it to the antenna to complete backscattering; after the backscattering is completed, the control unit controls the tag-end device to enter the wake-up state.

[0043] The specific steps of using the present invention to communicate are described below:

[0044] Step 1

[0045] The antenna continuously receives radio frequency signals in the environment. The signal passes through the power divider and enters the energy acquisition unit for radio frequency energy acquisition. After the signal is rectified into direct current, it is boosted by the power management chip and stored in the capacitor to power the device.

[0046] Step 2

[0047] Assume that the control signal of the control unit

[0048]

[0049] The default control signal c(t) = 00. The device is in the wake-up state. The RFc1 port of SPDT switch 1 is connected to the RFc2 port of SPDT switch 2, and the RFc2 port of SPDT switch 2 is connected to the RFs21 port, which are then connected to the wake-up unit input. The energy management unit only supplies power to the wake-up unit and the control unit MCU.

[0050] Step 3

[0051] When the antenna receives the ASK signal, the signal passes through the other path of the power splitter and enters the wake-up unit. Figure 3 The wake-up unit of the present invention receives the signal waveform, Figure 4 The low-frequency sine wave with a frequency of 30kHz is obtained by envelope detection of the wake-up unit. When the low-frequency sine wave enters the input end of the wake-up device, the wake-up device will generate the following Figure 5 The pulse signal shown is sent to the MCU, waking the MCU from sleep state and entering low-power operation state.

[0052] To ensure that the device's wake-up unit has a large dynamic range, the receiver sensitivity of the wake-up unit is tested. Receiver sensitivity refers to the minimum input power of the receiver under the minimum signal-to-noise ratio required by the demodulator front end of a given receiver. The calculation formula is as follows, where NF is the noise figure, B is the signal bandwidth, and SNR is the receiver sensitivity. out,min This is the minimum signal-to-noise ratio required by the demodulator front end.

[0053] P in,min (dBm)=-174(dBm / Hz)+NF(dB)+10logB+SNR out,min (dB)

[0054] When measuring the sensitivity of the wake-up unit, reduce the signal power input to the antenna port until the wake-up device can no longer send a wake-up signal to the MCU. At this time, the input signal to the antenna port is the sensitivity of the wake-up unit. After testing, the receiving sensitivity of the wake-up unit of the device is -54dBm.

[0055] Step 4

[0056] After the MCU enters the low-power operation state, the control signal c(t) = 01, which controls the RFc2 port of the single-pole double-throw switch 2 to be connected to the RFs22 port. At this time, the antenna is connected to the downlink signal receiving channel of the communication unit, the device enters the receiving state, and the energy management unit supplies power to the MCU and the downlink signal receiving channel of the communication unit.

[0057] When the antenna receives the ASK modulated broadcast signal, the signal is amplified, matched, envelope detected and compared in the receiving channel, and then demodulated into a low-frequency square wave that enters the MCU for decoding.

[0058] The sensitivity of the device's downlink signal receiving channel was tested. When measuring the sensitivity of the communication unit's receiving channel, the signal power input to the antenna port was reduced until the MCU could no longer demodulate the received broadcast signal. The input signal at the antenna port at this point represents the sensitivity of the communication unit's downlink signal receiving channel. The test showed that the receiving sensitivity of the communication unit's receiving channel was -44dBm.

[0059] Step 4

[0060] After decoding is completed, the control signal c(t) = 1x, the MCU controls the RFc1 port of the single-pole double-throw switch 1 to connect to the RFs12 port, and then connects to the backscatter output end of the communication unit. At this time, the device enters the backscatter state, and the energy management unit supplies power to the sensor, MCU and communication unit backscatter channel.

[0061] The sensor starts working and transmits the collected information to the MCU through the I2C protocol. The MCU encodes the sensor information and sends it to the communication unit. At this time, the device receives the carrier. The MCU controls the two RF switches on the backscatter channel to modulate the sensor information to obtain the ASK signal, and sends it to the antenna to backscatter the sensor information outward.

[0062] In order to overcome the backscatter self-interference problem, a backscatter 2ASK modulation unit is provided as a backscatter modulation unit, which realizes high sensitivity reception of the shared antenna by frequency shifting. Figure 6 shown.

[0063] like Figure 6 As shown, the active backscatter 2ASK modulation device includes a common antenna for both transmission and reception, a three-port circulator serving as a signal directional transmission isolation module, and a switch amplifier modulation circuit. The switch amplifier modulation circuit comprises a circuit switching unit consisting of single-pole double-throw switches a and b, a non-output reflection signal terminal, and a filter amplifier unit consisting of a low-power amplifier 1, a filter, and a low-power amplifier 2 connected in sequence. The non-output reflection signal terminal is connected to two matched loads. The switch amplifier modulation circuit also includes a carrier signal input, a modulation signal input, a modulated signal input, a frequency shift signal input, and a backscatter signal output. The circuit switching unit receives two different control signals from the control module to independently control single-pole double-throw switches a and b, thereby achieving signal modulation and frequency shifting.

[0064] The control module generates two control signals, control signal 1 and control signal 2, which are output to the backscatter modulation unit. Control signal 1 is the user modulation signal, i.e., the 2ASK modulation signal, which is used to control single-pole double-throw switch a to implement the ASK modulation function. Control signal 2 is a square wave signal of a certain frequency, i.e., a frequency shift signal, which is used to control single-pole double-throw switch b to achieve frequency shifting. The control signal 1 output terminal of the control module is output to the modulation signal input terminal of the line switching unit, and the control signal output terminal 2 is output to the frequency shift signal input terminal of the line switching unit. The switch amplification modulation circuit is used to receive the control signal provided by the control module to modulate the carrier, shift the frequency, and then perform power amplification.

[0065] The antenna is connected to the antenna through port 1 of a three-port circulator, port 2 of the circulator is connected to the carrier signal input end of the switch amplifier modulation circuit, and port 3 of the circulator is connected to the backscatter signal output end.

[0066] Each single-pole double-throw switch a and b consists of three ports: one fixed port and two movable ports, the first movable port and the second movable port. The fixed port of single-pole double-throw switch a serves as the carrier signal input port, the first movable port of single-pole double-throw switch a serves as the modulation signal input port, and the second movable port is connected to the no-output reflection signal terminal. Single-pole double-throw switch a controls the carrier signal input port to be connected to the modulation signal input port or the no-output reflection signal terminal. The first movable port of single-pole double-throw switch a is connected to the fixed port of single-pole double-throw switch b. The fixed port of single-pole double-throw switch b serves as the modulated signal input port, the first movable port of single-pole double-throw switch b serves as the frequency-shifted signal input port, and the second movable port is connected to the no-output reflection signal terminal. Single-pole double-throw switch b controls the modulated signal input port to be connected to the frequency-shifted signal input port or the no-output reflection signal terminal. The second moving end of the single-pole double-throw switch b is connected to the input end of the low-power amplifier 1, the output end of the low-power amplifier 1 is connected to the input end of the filter, the output end of the filter is connected to the input end of the low-power amplifier 2, and the output end of the low-power amplifier 2 is connected to the backscatter signal output end.

[0067] When the 2ASK modulation signal is 1, the fixed end of the single-pole double-throw switch a is connected to the first moving end, and the fixed port of the single-pole double-throw switch b is connected to its first moving end. The carrier from the antenna and the 2ASK modulation signal from the control module are modulated to generate a 2ASK modulated signal to the modulated signal input end. The 2ASK modulated signal is frequency-shifted by the frequency shift signal from the control module and then filtered and amplified by two low-power amplifiers and filters in the on state to form a frequency-shifted backscattered 2ASK modulated signal to the backscattered signal output end, and finally radiated into space through the antenna.

[0068] When the 2ASK modulated signal is 0, the fixed end of the single-pole double-throw switch a is connected to its second movable end, and the fixed end of the single-pole double-throw switch b is connected to its second movable end. The second movable ends of the single-pole double-throw switches a and b are respectively connected to the matching loads. The low-power amplifier is in the disconnected state. The carrier signal received by the antenna is absorbed by the matching load, and the antenna has no signal output.

[0069] In the embodiment, the control unit of the tag device outputs a control signal 1 to change the state of the single-pole double-throw switch a in the backscatter modulation unit, effectively realizing the modulation of the 2ASK signal; the control unit outputs a control signal 2 to change the state of the single-pole double-throw switch b in the device, effectively realizing the frequency shift of the 2ASK signal, and filtering out some of the other useless frequency components introduced when the single-pole double-throw switches a and b are switched through the filter, thereby ensuring that the frequency output by the switch amplification modulation module is clean; a low-power amplifier module is added, on the one hand, to compensate for the loss introduced by the switch switching modulation process and the filter, and on the other hand, to isolate the signal transmitted in the reverse direction of the circulator to prevent it from entering the switch to participate in the modulation and introducing other useless frequency components.

[0070] Assume that the carrier signal received by the antenna (taking a single tone as an example) is A0cos(2πf c t+θ). The frequency shift signal is of frequency f c2 The square wave transmitted by the antenna s(t) can be expressed as:

[0071] s(t)=A·c1(t)·cos(2π(f c t±f c2 )t+θ+ξ)

[0072] Where A is the transmit signal amplitude, which is related to the control signal amplitude, circulator losses, and other actual circuit losses. ξ is the phase change caused by reflection and circuit transmission. The expression shows that the transmit signal is a 2ASK signal modulated by the control signal. The envelope characteristics of this modulated signal are consistent with the modulation waveform input by the control module.

[0073] The time domain waveform of the backscattered modulation signal of the communication unit is as follows: Figure 7 shown. Figure 8 This is the spectrum diagram of the backscatter modulation signal, where the 468MHz signal is the carrier and the 473MHz signal is the backscatter signal generated by the device.

[0074] The device described in the present invention has high sensitivity and can work without batteries. It realizes radio frequency power acquisition and communication through a common antenna, and gets rid of the dependence of sensor nodes on batteries.

Claims

1. A battery-free, ultra-low power consumption, radio frequency power-taking, and shared antenna tag device, characterized in that: It includes an antenna, a power splitter, an energy acquisition unit, an energy management unit, a switching unit, a wake-up unit, a sensor, a communication unit and a control unit; the communication unit includes a backscatter signal modulation unit and a downlink signal demodulation unit; The antenna is connected to the input end of the energy acquisition unit and the switching unit through a power splitter; the switching unit is used to switch the connection between the input end of the wake-up unit, the backscattered signal modulation unit, and the input end of the downlink signal demodulation unit; the control unit is respectively connected to the output end of the wake-up unit, the output end of the sensor, the modulation signal input end of the backscattered signal modulation unit of the communication unit, and the output end of the downlink signal demodulation unit; the energy management unit is used to power the communication unit, the wake-up unit, the sensor, and the control unit; The tag-end device is initially in a waiting state. When the tag-end device is in the waiting state, the energy management unit only supplies power to the wake-up unit and the control unit. The control unit controls the switching unit to connect the antenna and the wake-up unit, and the control unit is in a dormant state. When the wake-up unit receives a wake-up signal from the antenna, the wake-up unit sends a pulse signal to the control unit, and the control unit controls the tag-end device to enter a receiving state. When the tag-end device is operating in a receiving state, the energy management unit supplies power to the control unit and the downlink signal demodulation unit. The control unit controls the switching unit to connect the antenna and the downlink signal demodulation unit, and the control unit operates in a low-power operation state. The downlink signal demodulation unit demodulates the radio frequency signal from the antenna and outputs the demodulated signal to the control unit for decoding. After the control unit completes decoding, it controls the tag end device to enter the backscattering state; When the tag-end device operates in the backscattering state, the energy management unit supplies power to the control unit, the sensor and the backscattering signal modulation unit. The control unit controls the switching unit to connect the antenna and the backscattering signal modulation unit. The sensor transmits the collected information to the control unit. The control unit processes the collected information into a modulation signal and outputs it to the modulation signal input end of the backscattering signal modulation unit. The backscattering signal modulation unit receives the carrier from the antenna and the modulation signal from the control unit, modulates them, generates a modulated signal, and outputs it to the antenna to complete backscattering. After the backscattering is completed, the control unit controls the tag end device to enter the wake-up state.

2. The label end device according to claim 1, characterized in that: The wake-up signal is a 2ASK signal; the modulation signal output by the control unit is a 2ASK modulation signal.

3. The label end device according to claim 2, characterized in that: The control unit is further configured to output a frequency shift signal; the control unit includes a first control signal output terminal and a second control signal output terminal; the control unit outputs a 2ASK modulated signal through the first control signal output terminal and outputs a frequency shift signal through the second control signal output terminal; The backscatter signal modulation unit includes a signal directional transmission isolation module and a switch amplification modulation circuit; the antenna is connected to the signal directional transmission isolation module through a power divider; the switch amplification modulation circuit includes a circuit switching unit, a carrier signal input terminal, a modulation signal input terminal, a modulated signal input terminal, a frequency shift signal input terminal, a non-output reflection signal terminal, a filtering and amplification unit, and a backscatter signal output terminal; The first control signal output terminal of the control unit outputs a 2ASK modulation signal to the modulation signal input terminal of the line switching unit, and the second control signal output terminal outputs a frequency shift signal to the frequency shift signal input terminal of the line switching unit; The antenna is connected to the carrier signal input terminal and the backscatter signal output terminal through the signal directional transmission isolation module, the modulation signal input terminal is connected to the modulated signal input terminal, the frequency shift signal input terminal is connected to the input terminal of the filter amplifier unit, and the output terminal of the filter amplifier unit is connected to the backscatter signal output terminal; the line switching unit controls the carrier signal input terminal to be connected to the modulation signal input terminal or to the no-output reflection signal terminal, and controls the modulated signal input terminal to be connected to the frequency shift signal input terminal or to the no-output reflection signal terminal.

4. The label end device according to claim 3, characterized in that: When the 2ASK modulation signal is 1, the line switching unit controls the carrier signal input terminal to be connected to the modulation signal input terminal, and controls the modulated signal input terminal to be connected to the frequency shift signal input terminal. The carrier from the antenna and the 2ASK modulation signal from the control unit are modulated to generate a 2ASK modulated signal to the modulated signal input terminal. The 2ASK modulated signal is frequency-shifted by the frequency shift signal from the control unit, and then passes through the filtering and amplifying unit to form a frequency-shifted backscattered 2ASK modulated signal to the backscattered signal output terminal, and finally radiated into space through the antenna. When the 2ASK modulation signal is 0, the line switching unit controls the carrier signal input terminal and the modulated signal input terminal to be connected to the no-output reflected signal terminal.

5. The label end device according to claim 1, characterized in that: The downlink signal demodulation unit completes demodulation by performing signal amplification, matching, envelope detection and comparison on the input RF signal.

6. The label end device according to claim 1, characterized in that: The switching unit consists of a first single-pole double-throw switch and a second single-pole double-throw switch; the fixed end of the first single-pole double-throw switch is connected to the power divider, one movable end of the first single-pole double-throw switch is connected to the fixed end of the second single-pole double-throw switch, and the other movable end is connected to the modulation signal input end of the backscatter signal modulation unit; one movable end of the second single-pole double-throw switch is connected to the wake-up unit, and the other movable end is connected to the input end of the downlink signal demodulation unit.

7. The label end device according to claim 1, characterized in that: The energy acquisition unit includes a matching network and a rectifier-boost circuit; the antenna is connected to the rectifier-boost circuit through the matching network; the rectifier-boost circuit converts the RF signal into DC power and increases the voltage, and a Schottky diode is selected for use in the rectifier module.

8. The label end device according to claim 1, wherein: The energy management unit includes a power management chip and a supercapacitor. The antenna is connected to the supercapacitor through the power management chip. The electric energy from the energy acquisition unit is boosted and output by the power management chip. When the voltage reaches the set value, it is input into the supercapacitor for energy storage.

9. The label end device according to claim 1, wherein: The wake-up unit includes an envelope detection module and a wake-up device; the switching unit is connected to the wake-up device through the envelope detection module; the wake-up device works in the monitoring mode, and envelope detection is added before the wake-up device; when the antenna receives the carrier signal, the carrier signal is processed into a low-frequency carrier after envelope detection and output to the wake-up device for wake-up.

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