Ultra-long-distance read-write electronic tag

Abstract

The utility model relates to an ultra-long-distance read-write electronic tag, which belongs to the technical field of electronic tags and comprises an antenna, a radio frequency front end, a power management module, a battery, a signal strength detector, a power amplifier and a change-over switch. And the signal strength detector is used for detecting the strength of the received signal, controlling the change-over switch to be communicated with the power amplifier when the strength of the received signal is lower than a preset threshold value, performing power amplification on the signal output by the radio frequency front end, and then transmitting the signal. According to the invention, the communication distance of the electronic tag is increased, the energy consumption is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present application relates to the field of electronic tags, and in particular to a method and a related device for enhancing functions of electronic devices. Background Art

[0002] With the development of Internet of Things technology, electronic tags, as an important part of the Internet of Things, have been widely used in warehousing logistics, manufacturing, asset management and other fields. Electronic tags realize data interaction with readers through wireless communication technology, so that the information of items can be automatically and quickly identified and collected.

[0003] The common electronic tag system currently consists of two parts: the electronic tag and the reader. The electronic tag exchanges data with the reader through wireless communication technology. After the electronic tag receives the wireless signal from the reader, it will process the signal internally and perform corresponding operations according to the received instructions, such as sending data to the reader.

[0004] However, current electronic tags have some limitations in practical applications. On the one hand, the transmission power of the electronic tag itself is small, resulting in a limited communication distance. If active electronic tags are used, the working time of the electronic tags is limited due to the limited battery capacity. Frequent battery replacement not only increases the maintenance cost, but also brings inconvenience to use. Utility Model Content

[0005] The present application provides an ultra-long-distance read-write electronic tag, which can not only extend the communication distance of the electronic tag but also reduce power consumption to extend the battery life.

[0006] In the first aspect, the present application provides an ultra-long-distance read-write electronic tag, comprising an antenna, a radio frequency front end, a microcontroller, a power management module and a battery, and a memory connected to the microcontroller, and the electronic tag also includes a switching switch, a power amplifier and a signal strength detector; wherein the antenna is used to receive and send radio frequency signals, and is electrically connected to the output end of the power amplifier and the switching switch respectively; the radio frequency front end is used to demodulate, filter and other processes on the received radio frequency signal, and modulate the signal to be sent, one end of which is electrically connected to the input end of the power amplifier through the switching switch, and the other end is electrically connected to the microcontroller; the switching switch is electrically connected to the power supply end and input end of the power amplifier, the antenna, the power management module and the signal strength detector respectively, and is used to select to open the first switch path or the second switch path according to the control signal sent by the signal strength detector; when the first switch path is turned on, the radio frequency front end is directly connected to the antenna through the switching switch; When the second switch path is turned on, the RF front end is connected to the antenna through the switching switch and the power amplifier, and the power management module supplies power to the power amplifier through the switching switch; the signal strength detector is used to detect the signal strength of the read signal received from the electronic tag reader, and when the signal strength is detected to be higher than the built-in threshold, a control signal for turning on the first switch path is sent to the switching switch, and when the signal strength is detected to be not higher than the built-in threshold, a control signal for turning on the second switch path is sent to the switching switch; the power management module is used to manage the power from the battery and provide a stable operating voltage for the microcontroller, the RF front end and the power amplifier; the microcontroller is electrically connected to the RF front end, the memory and the power management module respectively, and is used to control various functions of the electronic tag, including control of the RF front end and read and write operations on the memory; the memory is used to store identification information of the electronic tag and other data that needs to be stored.

[0007] By adopting the above technical solution, the electronic tag can adaptively choose whether to enable the power amplifier according to the received reader signal strength. When the signal strength is high, the electronic tag communicates directly through the RF front end and the antenna, saving the energy consumption of the power amplifier; when the signal strength is low, the electronic tag connects the power amplifier to the RF path by switching the switch to increase the transmission power and expand the communication distance. This method of dynamic adjustment according to actual needs can not only expand the communication range, but also avoid the additional power consumption caused by the continuous operation of the power amplifier, thereby reducing power consumption while expanding the communication distance of the electronic tag and extending the battery life.

[0008] In combination with some embodiments of the first aspect, in some embodiments, the antenna is a distributed antenna, and an impedance matching circuit is also connected between the RF front end and the switching switch, and the impedance value of the impedance matching circuit matches the impedance value of the distributed antenna.

[0009] By adopting the above technical solution, a distributed antenna and an impedance matching circuit are introduced. The distributed antenna distributes multiple sub-antenna units on the electronic tag. Compared with a single antenna, a larger antenna size and higher gain can be obtained, which helps to increase the communication distance. At the same time, the impedance matching circuit matches the impedance of the RF front end with the distributed antenna, reducing the signal reflection caused by impedance mismatch, improving the signal transmission efficiency, and further increasing the communication distance. The combination of the distributed antenna and the impedance matching circuit maximizes the performance of the antenna and realizes ultra-long-distance electronic tag reading and writing.

[0010] In combination with some embodiments of the first aspect, in some embodiments, the distributed antenna includes several sub-antenna units and a feeding network, wherein: the sub-antenna units are rectangular microstrip patch antennas, and their number is 4 to 8; the feeding network adopts a microstrip line structure, which is used to connect each of the sub-antenna units to the impedance matching circuit.

[0011] By adopting the above technical solution, the sub-antenna unit adopts a rectangular microstrip patch antenna with a number of 4 to 8, which not only ensures a certain gain but also controls the antenna size. The feeding network adopts a microstrip line structure to connect the sub-antenna unit to the impedance matching circuit, with low transmission loss. The entire distributed antenna structure is simple and compact, easy to manufacture and integrate. By reasonably setting the size, number and arrangement of the sub-antenna unit, and matching the feeding network, the distributed antenna achieves high gain and low loss performance within the limited space of the electronic tag, providing a reliable antenna solution for ultra-long-distance communication.

[0012] In combination with some embodiments of the first aspect, in some embodiments, the length of each sub-antenna unit is 1 / 4 wavelength to 1 / 2 wavelength, and the width is 1 / 10 wavelength to 1 / 8 wavelength, where the wavelength is the free space wavelength corresponding to the operating frequency of the electronic tag; the sub-antenna units are arranged in a straight array along the length direction of the electronic tag, and the distance between two adjacent sub-antenna units is 1 / 8 wavelength to 1 / 4 wavelength.

[0013] By adopting the above technical solution, the parameters of the distributed antenna and the structure of the feeding network are further optimized. The length, width and spacing of the sub-antenna units are reasonably set according to the wavelength of the operating frequency, so that it can achieve good radiation effect within the expected frequency band.

[0014] In combination with some embodiments of the first aspect, in some embodiments, the feeding network includes a main feeder and several branch feeders, wherein: one end of the main feeder is connected to the impedance matching circuit, and the other end is open; one end of each of the branch feeders is connected to the main feeder, and the other end is connected to the feeding point of the corresponding sub-antenna unit; the connection point between the branch feeder and the main feeder is located in the middle position of the connection point of two adjacent sub-antenna units; the impedance matching circuit adopts a Π-type structure, including two series inductors and a parallel capacitor, and its impedance value is conjugate matched with the input impedance of the distributed antenna.

[0015] By adopting the above technical solution, the feeding network adopts the structure of main feeder and branch feeder, and the connection point between the branch feeder and the main feeder is located in the middle of the connection point of the adjacent sub-antenna unit, so as to realize the in-phase feeding of each sub-antenna unit and ensure the radiation directivity of the whole distributed antenna. The impedance matching circuit adopts the Π-type structure, realizes the impedance conjugate matching through two series inductors and one parallel capacitor, minimizes the reflection loss, and makes the performance of the distributed antenna fully exerted.

[0016] In combination with some embodiments of the first aspect, in some embodiments, the signal strength detector includes a radio frequency detector and a comparator; the radio frequency detector is used to detect the received radio frequency signal and input the detected voltage signal into the comparator; the comparator is used to compare the input voltage signal with a built-in threshold voltage, and output a high-level control signal when the detected voltage signal is not higher than the built-in threshold voltage.

[0017] By adopting the above technical solution, the signal strength detector can accurately determine the strength of the reader signal and provide a reliable basis for the control of the switching switch. The RF detector detects the received RF signal to obtain its amplitude information; the comparator compares the detected voltage signal with the built-in threshold voltage and outputs a control signal based on the comparison result. This signal strength detection method based on hardware circuit has fast response speed and low power consumption. It can monitor the change of signal strength in real time and trigger the state conversion of the switching switch in time. Combined with the switching switch and the power amplifier, the signal strength detector realizes the adaptive adjustment of the communication distance of the electronic tag, and can work flexibly and efficiently in different application scenarios.

[0018] In combination with some embodiments of the first aspect, in some embodiments, the switching switch includes a first analog switch, a second analog switch and a third analog switch, wherein: the control end of the first analog switch is connected to the output end of the signal strength detector, the input end is connected to the RF front end, and the output end is connected to the antenna; the control end of the second analog switch is connected to the output end of the signal strength detector, the input end is connected to the RF front end, and the output end is connected to the input end of the power amplifier; the control end of the third analog switch is connected to the output end of the signal strength detector, the input end is connected to the power management module, and the output end is connected to the power supply end of the power amplifier; when not triggered by a high-level control signal, the first analog switch is turned on, the second analog switch and the third analog switch are turned off, so that the RF front end is directly connected to the antenna through the first analog switch; when triggered by the high-level control signal, the first analog switch is turned off, the second analog switch and the third analog switch are turned on, so that the RF front end is connected to the antenna through the second analog switch and the power amplifier, and the power management module supplies power to the power amplifier through the third analog switch.

[0019] By adopting the above technical solution, the switching switch is composed of multiple analog switches, which can reliably control the RF path and the power path. The first and second analog switches are used to switch whether the RF front end is directly connected to the antenna or connected to the antenna through the power amplifier; the third analog switch is used to control whether to power the power amplifier. The conduction state of these analog switches is controlled by the output signal of the signal strength detector. When triggered by a high-level signal, the RF front end is connected to the antenna through the power amplifier, and the power management module powers the power amplifier at the same time; when not triggered by a high-level signal, the RF front end is directly connected to the antenna and the power amplifier is powered off. The design of the switching switch ensures the synchronization of RF path switching and power amplifier power supply control, avoids signal distortion or power amplifier damage due to timing problems, and improves the reliability and service life of the electronic tag.

[0020] In combination with some embodiments of the first aspect, in some embodiments, the battery is electrically connected to a photovoltaic panel, and the photovoltaic panel is used to charge the battery under light conditions.

[0021] By adopting the above technical solution, photovoltaic panels are introduced to charge the battery, thereby extending the working time of the electronic tag.

[0022] In combination with some embodiments of the first aspect, in some embodiments, the power management module includes a voltage conversion circuit and a charge and discharge management circuit, the voltage conversion circuit is used to convert the voltage of the battery into the operating voltage required by each module, and the charge and discharge management circuit is used to manage the charge and discharge process of the battery.

[0023] By adopting the above technical solution, the power management module includes a voltage conversion circuit and a charge and discharge management circuit, which can efficiently and safely manage the power supply of the battery and each module. The voltage conversion circuit converts the battery voltage into a stable operating voltage to meet the power supply requirements of each module; the charge and discharge management circuit controls the battery's charge and discharge process to avoid overcharging and overdischarging, thereby extending the battery's service life. Integrated power management simplifies the design of the electronic tag's power supply system, reduces the circuit board area, and improves energy conversion efficiency and reliability.

[0024] In combination with some embodiments of the first aspect, in some embodiments, the power management module also includes an undervoltage protection circuit, wherein: the undervoltage protection circuit is connected to the battery and is used to detect the voltage of the battery. When the battery voltage is lower than a preset undervoltage threshold, the undervoltage protection circuit cuts off the power management module's power supply to the signal strength detector and the power amplifier.

[0025] By adopting the above technical solution, an undervoltage protection circuit is added to the power management module, which can automatically shut down the power of non-critical modules when the battery power is low, thereby extending the working time of the electronic tag. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the structure of an electronic tag in an embodiment of the present application;

[0027] Figure 2 It is another structural schematic diagram of the electronic tag in the embodiment of the present application.

[0028] Explanation of the reference numerals: 110, antenna; 120, RF front end; 130, microcontroller; 140, power management module; 150, battery; 160, memory; 170, signal strength detector; 180, power amplifier; 190, switching switch; 210, distributed antenna; 220, impedance matching network; 230, photovoltaic panel. DETAILED DESCRIPTION

[0029] The following is combined with Figure 1-2 This application is described in further detail.

[0030] Example 1

[0031] The present application embodiment discloses an ultra-long distance read and write electronic tag. Figure 1The ultra-long-distance read-write electronic tag includes an antenna 110, a radio frequency front end 120, a microcontroller 130, a power management module 140, a battery 150, a memory 160, a switch 190, a power amplifier 180 and a signal strength detector 170. The antenna 110 is used to receive and send radio frequency signals, and is electrically connected to the output end of the power amplifier 180 and the switch 190 respectively; the radio frequency front end 120 is used to demodulate and filter the received radio frequency signals, and modulate the signals to be sent, one end of which is electrically connected to the input end of the power amplifier 180 through the switch 190, and the other end is electrically connected to the microcontroller 130; the switch 190 is electrically connected to the power amplifier 180 and the signal strength detector 170 respectively. The power supply end and input end, antenna 110, power management module 140 and signal strength detector 170 are electrically connected; the signal strength detector 170 is used to detect the signal strength of the read signal sent by the received electronic tag reader and send a control signal to the switching switch 190; the power management module 140 is used to manage the power from the battery 150 and provide a stable operating voltage for the microcontroller 130, the RF front end 120 and the power amplifier 180; the microcontroller 130 is electrically connected to the RF front end 120, the memory 160 and the power management module 140 respectively, and is used to control various functions of the electronic tag; the memory 160 is used to store the identification information of the electronic tag and other data that needs to be stored.

[0032] Under the control of the switch 190, the electronic tag can switch between two working modes. When the signal strength detector 170 detects that the reader signal strength is higher than the built-in threshold, the switch 190 opens the first switch path, so that the RF front end 120 is directly connected to the antenna 110. At this time, the power amplifier 180 is in a power-off state, and the RF signal does not undergo power amplification; when the signal strength detector 170 detects that the reader signal strength is not higher than the built-in threshold, the switch 190 opens the second switch path, so that the RF front end 120 is connected to the antenna 110 through the power amplifier 180, and the power management module 140 supplies power to the power amplifier 180, and the RF signal is sent after power amplification.

[0033] The implementation principle of an ultra-long-distance read-write electronic tag in an embodiment of the present application is as follows: the electronic tag receives the radio frequency reading signal sent by the reader through the antenna 110, and the signal strength detector 170 detects the strength of the signal, and outputs different control signals to the switching switch 190 according to the strength. If the signal strength is high, it means that the reader is close, and the switching switch 190 directly connects the radio frequency front end 120 to the antenna 110 and disconnects the power supply of the power amplifier 180, so that the radio frequency signal does not undergo power amplification to save power consumption; if the signal strength is low, it means that the reader is far away, and the switching switch 190 connects the radio frequency front end 120 to the input end of the power amplifier 180, and then connects the output of the power amplifier 180 to the antenna 110, and at the same time turns on the power supply of the power amplifier 180, so that the radio frequency signal is sent after power amplification to expand the communication distance. After demodulating and filtering the received RF signal, the RF front end 120 transmits the data to the microcontroller 130. The microcontroller 130 can read and write the data in the memory 160 according to the received instructions, and can also control the RF front end 120 to modulate the data of the electronic tag into the RF signal and send it out. The power management module 140 is responsible for converting the power of the battery 150 into a stable voltage required for the operation of each module. By dynamically controlling the power amplifier 180 through the switching switch 190, the electronic tag can adaptively adjust its communication distance and power consumption in different usage scenarios, achieving long-distance communication while also taking into account energy efficiency.

[0034] Example 2

[0035] Reference Figure 2 The difference between this embodiment and Embodiment 1 is that the antenna 110 may be a distributed antenna 210 , and an impedance matching network 220 is further connected between the RF front end 120 and the switch 190 .

[0036] Preferably, the distributed antenna 210 includes a plurality of sub-antenna units and a feeding network, wherein the sub-antenna units are rectangular microstrip patch antennas, and the number thereof is 4 to 8; the feeding network adopts a microstrip line structure, and is used to connect each sub-antenna unit to the impedance matching network 220.

[0037] For example, the sub-antenna unit can be a rectangular patch antenna made of PCB board, working in the 915MHz frequency band, with a size of 85mm×12mm (length×width), using 4 or 8 sub-antenna units. The feeding network uses a microstrip line with a characteristic impedance of 50Ω to connect each sub-antenna unit to a common feeding point.

[0038] Furthermore, the length of each sub-antenna unit is 1 / 4 wavelength to 1 / 2 wavelength, and the width is 1 / 10 wavelength to 1 / 8 wavelength, where the wavelength is the free space wavelength corresponding to the operating frequency of the electronic tag; the sub-antenna units are arranged in a straight array along the length direction of the electronic tag, and the distance between two adjacent sub-antenna units is 1 / 8 wavelength to 1 / 4 wavelength.

[0039] For example, for the 915MHz frequency band, the length of the sub-antenna unit can be 82mm (about 1 / 4 wavelength) or 164mm (about 1 / 2 wavelength), and the width can be 16mm (about 1 / 10 wavelength); the distance between the sub-antenna units can be 41mm (about 1 / 8 wavelength) or 82mm (about 1 / 4 wavelength). Such size and spacing settings can form directional radiation in the length direction of the electronic tag and improve the antenna gain.

[0040] Preferably, the feeding network includes a main feeder and several branch feeders, one end of the main feeder is connected to the impedance matching network 220, and the other end is open; one end of each branch feeder is connected to the main feeder, and the other end is connected to the feeding point of the corresponding sub-antenna unit; the connection point between the branch feeder and the main feeder is located in the middle of the connection points of two adjacent sub-antenna units. The impedance matching network 220 can be designed with a Π-type structure, so that it includes two series inductors and a parallel capacitor, and its impedance value is conjugate matched with the input impedance of the distributed antenna 210.

[0041] For example, the main feed line and the branch feed line can both use 50Ω microstrip lines, and the main feed line and the branch feed line are vertically connected. The two inductors of the Π-type matching network can use 8.2nH 0603 package high-frequency inductors, and the parallel capacitors can use 2.2pF 0603 package high-frequency capacitors. Through these component values, the antenna input impedance can be transformed from a complex form to a 50Ω pure resistance to match the RF front end.

[0042] Preferably, the signal strength detector 170 includes a radio frequency detector and a comparator; the radio frequency detector is used to detect the received radio frequency signal and input the detected voltage signal into the comparator; the comparator is used to compare the input voltage signal with the built-in threshold voltage, and output a high-level control signal when the detected voltage signal is not higher than the built-in threshold voltage.

[0043] For example, the RF detector can use the HSMS-2850 zero-bias Schottky detector diode, which has high sensitivity and low threshold voltage. The comparator can use the LMV7219 nanoampere-level low-power comparator, and use its internal integrated voltage regulator to provide the threshold voltage, setting the threshold to 0.5V. When the detection voltage is lower than the threshold, the comparator outputs a high level.

[0044] Further, the switching switch 190 may include a first analog switch, a second analog switch and a third analog switch. The control end of the first analog switch is connected to the output end of the signal strength detector 170, the input end is connected to the RF front end 120, and the output end is connected to the distributed antenna 210; the control end of the second analog switch is connected to the output end of the signal strength detector 170, the input end is connected to the RF front end 120, and the output end is connected to the input end of the power amplifier 180; the control end of the third analog switch is connected to the output end of the signal strength detector 170, the input end is connected to the power management module 140, and the output end is connected to the power supply end of the power amplifier 180. In the case of not being triggered by a high-level control signal, the first analog switch is turned on, and the second and third analog switches are turned off; in the case of being triggered by a high-level control signal, the first analog switch is turned off, and the second and third analog switches are turned on.

[0045] For example, the three analog switches can all use the ADG902 SPDT RF switch. The control end receives the output signal of the signal strength detector. The high level turns on the RF2 end, and the low level turns on the RF1 end. When the detection voltage is higher than the threshold, RF1 and RF2 of the first switch are turned on, and the antenna is directly connected to the RF front end; when the detection voltage is lower than the threshold, the first switch is disconnected, and RF1 and RF2 of the second and third switches are turned on, and the RF front end output is fed to the antenna after power amplification.

[0046] Preferably, the battery 150 is electrically connected to the photovoltaic panel 230, and the photovoltaic panel 230 is used to charge the battery 150 under light conditions.

[0047] For example, the battery 150 may be a 3.7V 500mAh polymer lithium-ion battery, and the photovoltaic panel 230 may be a 5V 100mA monocrystalline silicon photovoltaic module with a size of 60mm×60mm, and the battery can be charged in an outdoor environment.

[0048] In addition, the power management module 140 may include a voltage conversion circuit and a charge and discharge management circuit. The voltage conversion circuit is used to convert the voltage of the battery 150 into the working voltage required by each module, and the charge and discharge management circuit is used to manage the charge and discharge process of the battery 150.

[0049] For example, the voltage conversion circuit can use the MT3608 step-up DC-DC chip to boost the battery's 3.7V voltage to 5V to power each module. The charge and discharge management can use the TP4056 lithium battery charge management chip, which has constant current and constant voltage charging, charging current limit protection and other functions, and can safely and efficiently manage battery charging and discharging.

[0050] Furthermore, the power management module 140 may also include an undervoltage protection circuit, which is connected to the battery 150 and is used to detect the voltage of the battery 150. When the battery voltage is lower than a preset undervoltage threshold, the undervoltage protection circuit cuts off the power supply of the power management module 140 to the signal strength detector 170 and the power amplifier 180.

[0051] For example, the undervoltage protection circuit can use the S-8261ABJMD-G5TL-E undervoltage protection IC, and the detection voltage threshold is set to 3V. When the battery voltage is lower than this value, the output of the protection IC is cut off, and the power supply to the signal strength detector and the power amplifier is stopped to avoid over-discharge of the battery.

[0052] The implementation principle of Example 2 is: using a distributed antenna 210 to replace a single antenna. The distributed antenna 210 is composed of multiple sub-antenna units and a feeding network. The sub-antenna unit is a rectangular patch antenna with optimized size and spacing. This structure can obtain a higher directional gain in the length direction of the electronic tag, significantly improving the communication distance of the electronic tag; at the same time, an impedance matching network 220 is introduced to match the impedance of the RF front end 120 with the distributed antenna 210, reduce reflection loss, and improve antenna efficiency. A specific analog switch circuit can be used to realize the two working states of the switching switch 190, and the conduction and disconnection of each analog switch can be directly controlled by the comparison result of the signal strength detector 170. The photovoltaic panel 230 can be used to enable the electronic tag to charge the battery and replenish energy in a light environment, thereby extending the service life; the battery voltage is monitored by the undervoltage protection circuit, and the power supply to the signal strength detection and power amplification is automatically cut off when the voltage is too low, which can avoid over-discharge of the battery and protect the battery from damage.

[0053] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An ultra-long-distance read-write electronic tag, comprising an antenna, a radio frequency front end, a microcontroller, a power management module and a battery, and a memory connected to the microcontroller, characterized in that: The electronic tag also includes a switch, a power amplifier and a signal strength detector; wherein, The antenna is used to receive and send radio frequency signals, and is electrically connected to the output end of the power amplifier and the switch respectively; The RF front end is used to demodulate and filter the received RF signal and modulate the signal to be transmitted, one end of which is electrically connected to the input end of the power amplifier through the switching switch, and the other end is electrically connected to the microcontroller; The switching switch is electrically connected to the power supply end and the input end of the power amplifier, the antenna, the power management module and the signal strength detector respectively, and is used to select to open the first switch path or the second switch path according to the control signal sent by the signal strength detector; When the first switch path is turned on, the RF front end is directly connected to the antenna through the switch; When the second switch path is turned on, the RF front end is connected to the antenna through the switch and the power amplifier, and the power management module supplies power to the power amplifier through the switch; The signal strength detector is used to detect the signal strength of the read signal sent by the received electronic tag reader, and when the signal strength is detected to be higher than the built-in threshold, send a control signal to the switch to open the first switch path; when the signal strength is detected to be not higher than the built-in threshold, send a control signal to the switch to open the second switch path; The power management module is used to manage the power from the battery and provide a stable operating voltage for the microcontroller, the RF front end and the power amplifier; The microcontroller is electrically connected to the RF front end, the memory, and the power management module, respectively, and is used to control various functions of the electronic tag, including control of the RF front end and read and write operations on the memory; The memory is used to store the identification information of the electronic tag and other data that needs to be stored.

2. The ultra-long-distance read-write electronic tag according to claim 1, characterized in that: The antenna is a distributed antenna, and an impedance matching circuit is further connected between the RF front end and the switch, and the impedance value of the impedance matching circuit matches the impedance value of the distributed antenna.

3. The ultra-long-distance read-write electronic tag according to claim 2, characterized in that: The distributed antenna includes a plurality of sub-antenna units and a feeding network, wherein: The sub-antenna units are rectangular microstrip patch antennas, and the number thereof is 4 to 8; The feeding network adopts a microstrip line structure and is used to connect each of the sub-antenna units to the impedance matching circuit.

4. The ultra-long-distance read-write electronic tag according to claim 3, characterized in that: The length of each sub-antenna unit is 1 / 4 wavelength to 1 / 2 wavelength, and the width is 1 / 10 wavelength to 1 / 8 wavelength, where the wavelength is the free space wavelength corresponding to the operating frequency of the electronic tag; the sub-antenna units are arranged in a straight array along the length direction of the electronic tag, and the distance between two adjacent sub-antenna units is 1 / 8 wavelength to 1 / 4 wavelength.

5. The ultra-long-distance read-write electronic tag according to claim 4, characterized in that: The feeder network includes a main feeder and a plurality of branch feeders, wherein: One end of the main feeder is connected to the impedance matching circuit, and the other end is open; One end of each branch feeder is connected to the main feeder, and the other end is connected to the feeding point of the corresponding sub-antenna unit; The connection point between the branch feeder and the main feeder is located in the middle of the connection points of two adjacent sub-antenna units; The impedance matching circuit adopts a Π-type structure, including two series inductors and a parallel capacitor, and its impedance value is conjugate matched with the input impedance of the distributed antenna.

6. The ultra-long-distance read-write electronic tag according to claim 1, characterized in that: The signal strength detector includes a radio frequency detector and a comparator; The radio frequency detector is used to detect the received radio frequency signal and input the detected voltage signal into the comparator; The comparator is used to compare the input voltage signal with the built-in threshold voltage, and output a high-level control signal when the voltage signal after detection is not higher than the built-in threshold voltage.

7. The ultra-long-distance read-write electronic tag according to claim 6, characterized in that: The switching switch includes a first analog switch, a second analog switch and a third analog switch, wherein: The control end of the first analog switch is connected to the output end of the signal strength detector, the input end is connected to the RF front end, and the output end is connected to the antenna; The control end of the second analog switch is connected to the output end of the signal strength detector, the input end is connected to the RF front end, and the output end is connected to the input end of the power amplifier; The control end of the third analog switch is connected to the output end of the signal strength detector, the input end is connected to the power management module, and the output end is connected to the power supply end of the power amplifier; When not triggered by a high-level control signal, the first analog switch is turned on, and the second analog switch and the third analog switch are turned off, so that the RF front end is directly connected to the antenna through the first analog switch; When triggered by the high-level control signal, the first analog switch is disconnected, and the second analog switch and the third analog switch are turned on, so that the RF front end is connected to the antenna through the second analog switch and the power amplifier, and the power management module supplies power to the power amplifier through the third analog switch.

8. The ultra-long-distance read-write electronic tag according to claim 1, characterized in that: The battery is electrically connected to a photovoltaic panel, and the photovoltaic panel is used to charge the battery under light conditions.

9. The ultra-long-distance read-write electronic tag according to claim 8, characterized in that: The power management module includes a voltage conversion circuit and a charge and discharge management circuit. The voltage conversion circuit is used to convert the voltage of the battery into the working voltage required by each module, and the charge and discharge management circuit is used to manage the charge and discharge process of the battery.

10. The ultra-long distance read-write electronic tag according to claim 1, characterized in that: The power management module also includes an undervoltage protection circuit, wherein: the undervoltage protection circuit is connected to the battery and is used to detect the voltage of the battery. When the battery voltage is lower than a preset undervoltage threshold, the undervoltage protection circuit cuts off the power supply of the power management module to the signal strength detector and the power amplifier.

Images