RFID tag, tag reader, RFID method and system

Abstract

The present application discloses a radio frequency identification (RFID) tag, a tag reader, an RFID method and a system, which relate to the field of radio frequency identification technology and can solve the interference of the tag reader to the demodulated modulation signal caused by the self-interference problem. The RFID tag manages the working frequency (such as the first frequency) of the rectangular wave generator through a logic processing unit, generates an information bit stream and instructs the rectangular wave generator to output a square wave signal including the first frequency and / or a converted signal of a continuous low level according to the first frequency, so as to control the load switch to connect the first load or the second load with different impedance values, thereby controlling the frequency of the modulation signal transmitted to the tag reader. In this way, the frequency difference between the modulation signal and the self-interference signal of the tag reader can be ensured, so that the tag reader can simply and quickly filter the self-interference signal.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of radio frequency identification technology, and in particular to a radio frequency identification (RFID) tag, a tag reader, an RFID method and a system. Background Art

[0002] Radio Frequency Identification (RFID) is an automatic identification technology that uses induction, radio waves or microwaves for non-contact two-way communication for the purpose of identification and data exchange. The RFID system can be used to track and manage target objects.

[0003] The RFID system can include a tag reader, an RFID tag, and a host. The basic principle of RFID is that the tag reader transmits a radio frequency signal (such as a carrier signal) of a specific frequency through a transmitting antenna; after receiving the electromagnetic wave, the RFID tag will generate an induced current, thereby obtaining energy to modulate the information stored in the chip, and then transmit it through the built-in antenna. After receiving the modulated signal, the receiving antenna of the tag reader transmits it to the signal processing module of the tag reader, which completes the demodulation and decoding of the signal and transmits it to the host. Then, the host identifies the identity of the RFID tag based on logical operations, makes corresponding processing and control for different settings, and finally sends a signal to control the tag reader to complete different read and write operations.

[0004] However, when the tag reader receives the modulated signal sent by the RFID tag, it also receives the radio frequency signal emitted by the transmitting antenna. Since the modulated signal and the radio frequency signal are very close in frequency spectrum, for the tag reader with the transmitting antenna and the receiving antenna set at the same position, the radio frequency signal will interfere with the demodulation of the modulated signal by the tag reader. Summary of the invention

[0005] The present application provides an RFID tag, a tag reader, an RFID method and a system, which can solve the interference of the tag reader to the demodulated modulation signal caused by the self-interference problem.

[0006] In order to achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, an RFID tag is provided, the RFID tag comprising: a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch including a control end and a connection end, and an antenna; the logic processing unit is connected to the rectangular wave generator, the logic processing unit is used to transmit an information bit stream to the rectangular wave generator, and instruct the rectangular wave generator to convert the information bit stream into a square wave signal of a first frequency or a low level; the rectangular wave generator is connected to the control end of the load switch; the rectangular wave generator is used to receive the information bit stream, convert a first identifier in the information bit stream into a square wave signal of a first frequency, and convert a second identifier in the information bit stream into a square wave signal of a first frequency. The signal is converted into a low level, and the converted signal is transmitted to the control end of the load switch; wherein the converted signal is used to control the connection end of the load switch to connect the first load or the second load, so that the antenna is connected to the first load or the second load through the connection end of the load switch; the load switch is used to connect the first load or the second load through the connection end according to the converted signal; the antenna is used to send a modulated signal to the tag reader according to the situation that the load switch connects the first load and the second load; wherein the resistance difference between the first load and the load of the antenna is less than a first preset threshold, and the resistance difference between the second load and the load of the antenna is greater than a second preset threshold.

[0008] In the technical solution provided in the first aspect above, the RFID tag manages the operating frequency (such as the first frequency) of the rectangular wave generator through the logic processing unit, generates an information bit stream, and instructs the rectangular wave generator to output a square wave signal including the first frequency and / or a converted signal of a continuous low level according to the first frequency, so as to control the load switch to connect the first load or the second load with different impedance values, thereby controlling the frequency of the modulated signal transmitted to the tag reader. In this way, the frequency difference between the modulated signal and the self-interference signal of the tag reader can be ensured, so that the tag reader can simply and quickly filter the self-interference signal.

[0009] In a possible implementation, the rectangular wave generator includes: a configuration port, an enable port, and an output port; the rectangular wave generator is connected to the logic processing unit through the configuration port and the enable port respectively; the rectangular wave generator is connected to the control end of the load switch through the output port; the configuration port is used to receive the first frequency configured by the logic processing unit; the enable port is used to receive the information bit stream output by the logic processing unit; the output port is used to transmit the converted signal to the control end of the load switch. The rectangular wave generator accepts the management (such as adjustment) of its operating frequency by the logic processing unit through the configuration port set thereon, obtains the information bit stream from the logic processing unit through the enable port, and transmits its converted signal to the control end of the load switch through the output port. Through such a design, the rectangular wave generator can flexibly output a signal for controlling the load switch to connect or not connect the load.

[0010] In a possible implementation, the first identifier is a binary number "1", and the second identifier is a binary number "0"; or, the first identifier is a binary number "0", and the second identifier is a binary number "1".

[0011] In a possible implementation, the load switch is specifically used to: turn on the first load when the converted signal indicates a high level of the first frequency; turn on the second load when the square wave signal indicates a low level of the first frequency; keep the second load turned on when the converted signal indicates a continuous low level; or turn on the first load when the converted signal indicates a low level of the first frequency; turn on the second load when the square wave signal indicates a high level of the first frequency; keep the first load turned on when the converted signal indicates a continuous low level. Through such a control method, the RFID tag can output a modulation signal with a different frequency from the radio frequency signal from the tag reader when the information bit stream indicates a binary number "1", so that the tag reader can eliminate interference and demodulate the modulation signal smoothly.

[0012] In a possible implementation, the antenna is specifically used to: receive a radio frequency signal of a second frequency from a tag reader, and, when the load switch switches between the first load and the second load at the first frequency, send a modulation signal of a third frequency to the tag reader; when the load switch is connected to the first load for a time period greater than a preset time period, send a modulation signal of a second frequency to the tag reader; wherein the third frequency = first frequency + second frequency. Through such a control method, the RFID tag can output a modulation signal of a frequency different from the radio frequency signal from the tag reader when the information bit stream indicates a binary number "1", so that the tag reader can smoothly eliminate interference and demodulate the modulation signal.

[0013] In a second aspect, a tag reader is provided, which includes: a logic processing unit, a receiver, a transmitter and at least one antenna; the logic processing unit is connected to both the receiver and the transmitter; the receiver and the transmitter are connected to at least one antenna; the above-mentioned receiver includes: a bandpass filter, an envelope detector and a comparator, the bandpass filter is connected to the envelope detector, and the envelope detector is connected to the comparator; the bandpass filter is used to suppress the radio frequency signal from the transmitter and allow a first signal to pass; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector is used to convert one or more modulated signals in the first signal into envelope signals respectively; the comparator is used to demodulate according to the envelope signal and a preset reference voltage to obtain an information bit stream from one or more RFID tags; wherein the frequencies of the above-mentioned one or more modulated signals are all different.

[0014] According to the technical solution provided in the second aspect, the tag reader filters out the self-interference signal through a bandpass filter according to the difference in frequency between the self-interference signal and the modulation signal from the RFID tag, and retains the modulation signal from the RFID tag, thereby simply and quickly filtering the self-interference signal to avoid interference caused by the sub-interference signal in the tag reader demodulating the modulation signal from the RFID tag.

[0015] In a possible implementation, the tag reader further includes: a self-interference elimination circuit; the self-interference elimination circuit is arranged between the transmitter and the receiver; the self-interference elimination circuit includes an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between the transmitter and the receiver; the analog self-interference elimination circuit is used to eliminate the analog radio frequency signal leaked from the transmitter to the receiver. By arranging the analog self-interference elimination circuit between the transmitter and the receiver to calculate the analog radio frequency signal leaked from the transmitter to the receiver, the interference caused by the leaked analog radio frequency signal to the receiver can be eliminated.

[0016] In a possible implementation, the tag reader includes a receiving antenna and a transmitting antenna; the receiver is connected to the receiving antenna, and the transmitter is connected to the transmitting antenna. The present application is also applicable to a tag reader with separate receiving and transmitting functions.

[0017] In a possible implementation, the receiving antenna and the transmitting antenna have different polarization directions. The receiving antenna and the transmitting antenna with different polarization directions are responsible for receiving and sending signals respectively, which can ensure the isolation between the receiving antenna and the transmitting antenna and reduce mutual interference.

[0018] In a possible implementation, the tag reader includes an antenna, and the receiver and the transmitter are both connected to the antenna. The present application is also applicable to a tag reader that uses the same antenna for receiving and transmitting.

[0019] In a possible implementation, the self-interference elimination circuit further includes: a transceiver port isolation circuit; the transceiver port isolation circuit is used to suppress the radio frequency signal of the transmitter coupled to the receiver. For a tag reader that uses the same antenna for receiving and transmitting, a transceiver port isolation circuit can be set at the interface of the antenna, receiver and transmitter to suppress the radio frequency signal of the transmitter coupled to the receiver.

[0020] In a possible implementation, the transceiver port isolation circuit includes a circulator; the circulator includes a first port, a second port, and a third port, the first port is connected to the transmitter, the second port is connected to the receiver, and the third port is connected to the antenna. The transceiver port isolation circuit composed of a circulator is provided at the interface of the antenna, the receiver, and the transmitter to suppress the radio frequency signal of the transmitter coupling to the receiver.

[0021] In a possible implementation, the one or more modulation signals include a modulation signal of a third frequency f3; the bandpass filter is specifically used to suppress the radio frequency signal from the transmitter and allow the modulation signal of the third frequency f3 to pass; the envelope detector is specifically used to convert the modulation signal of the third frequency f3 into an envelope signal; the comparator is specifically used to determine the RFID tag that sends the modulation signal of the third frequency f3 according to the envelope signal. The tag reader filters out the self-interference signal through a bandpass filter according to the difference in frequency between its self-interference signal and the modulation signal from the RFID tag, and retains the modulation signal from the RFID tag, thereby simply and quickly filtering the self-interference signal. Then, the modulation signal of the third frequency f3 is converted into an envelope signal through the envelope detector, and finally, the information bit stream from the RFID tag that sends the modulation signal of the third frequency f3 is obtained by decoding through the comparator.

[0022] In a third aspect, an RFID method is provided, which is applied to an RFID tag, the RFID tag comprising: a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch comprises a control end and a connection end, the logic processing unit is connected to the rectangular wave generator, and the rectangular wave generator is connected to the control end of the load switch; the resistance difference between the first load and the load of the antenna is less than a first preset threshold, and the resistance difference between the second load and the load of the antenna is greater than a second preset threshold; the above method comprises: the logic processing unit transmits an information bit stream to the rectangular wave generator, and instructs the rectangular wave generator to convert the information bit stream into a first preset threshold; The rectangular wave generator receives the information bit stream, converts the first identifier in the information bit stream into a square wave signal of the first frequency, converts the second identifier in the information bit stream into a low level, and transmits the converted signal to the control end of the load switch; wherein the converted signal is used to control the connection end of the load switch to connect the first load or the second load, so that the antenna is connected to the first load or the second load through the connection end of the load switch; the load switch connects the first load or the second load through the connection end according to the converted signal; the antenna sends a modulated signal to the tag reader according to the situation that the load switch connects the first load and the second load.

[0023] In the technical solution provided in the third aspect, the RFID tag manages the operating frequency (such as the first frequency) of the rectangular wave generator through the logic processing unit, generates an information bit stream, and instructs the rectangular wave generator to output a square wave signal including the first frequency and / or a converted signal of a continuous low level according to the first frequency, so as to control the load switch to connect the first load or the second load with different impedance values, thereby controlling the frequency of the modulated signal transmitted to the tag reader. In this way, the frequency difference between the modulated signal and the self-interference signal of the tag reader can be ensured, so that the tag reader can simply and quickly filter the self-interference signal.

[0024] In a possible implementation, the load switch connects the first load or the second load through the connection end according to the converted signal, specifically including: when the converted signal indicates a high level of the first frequency, the load switch connects the first load through the connection end; when the square wave signal indicates a low level of the first frequency, the load switch connects the second load through the connection end; when the converted signal indicates a continuous low level, the load switch remains connected to the second load through the connection end; or, when the converted signal indicates a low level of the first frequency, the load switch connects the first load through the connection end; when the square wave signal indicates a high level of the first frequency, the load switch connects the second load through the connection end; when the converted signal indicates a continuous low level, the load switch remains connected to the first load through the connection end. Through such a control method, the RFID tag can output a modulation signal with a different frequency from the radio frequency signal from the tag reader when the information bit stream indicates a binary number "1", so that the tag reader can eliminate interference and demodulate the modulation signal smoothly.

[0025] In a possible implementation, the first identifier is a binary number "1", and the second identifier is a binary number "0"; or, the first identifier is a binary number "0", and the second identifier is a binary number "1".

[0026] In a possible implementation, the antenna sends a modulated signal to the tag reader according to the situation that the load switch is connected to the first load and the second load, specifically including: the antenna receives the radio frequency signal of the second frequency from the tag reader; if the load switch switches between the first load and the second load at the first frequency, the antenna sends a modulated signal of the third frequency to the tag reader; if the load switch is connected to the first load for a time period longer than a preset time period, the antenna sends a modulated signal of the second frequency to the tag reader; wherein the third frequency = the first frequency + the second frequency. Through such a control method, the RFID tag can output a modulated signal with a frequency different from the radio frequency signal from the tag reader when the information bit stream indicates the binary number "1", so that the tag reader can eliminate interference and demodulate the modulated signal smoothly.

[0027] In a fourth aspect, an RFID method is provided, which is applied to a tag reader, wherein the tag reader includes: a logic processing unit, a receiver, a transmitter and at least one antenna; the receiver includes: a bandpass filter, an envelope detector and a comparator, the bandpass filter is connected to the envelope detector, and the envelope detector is connected to the comparator; the method includes: the bandpass filter suppresses the radio frequency signal from the transmitter and allows a first signal to pass; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector converts one or more modulated signals in the first signal into envelope signals respectively; the comparator demodulates according to the envelope signal and a preset reference voltage to obtain an information bit stream from the one or more RFID tags; wherein the frequencies of the one or more modulated signals are all different.

[0028] The technical solution provided in the fourth aspect is that the tag reader filters out the self-interference signal through a bandpass filter according to the difference in frequency between the self-interference signal and the modulation signal from the RFID tag, and retains the modulation signal from the RFID tag, thereby simply and quickly filtering the self-interference signal to avoid interference caused by the sub-interference signal in the tag reader demodulating the modulation signal from the RFID tag.

[0029] In a possible implementation, the tag reader further includes: a self-interference elimination circuit; the self-interference elimination circuit is arranged between a transmitter and a receiver; the self-interference elimination circuit includes an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between a transmitter and a receiver; the method further includes: the analog self-interference elimination circuit eliminates the analog radio frequency signal leaked from the transmitter to the receiver. By arranging the analog self-interference elimination circuit between the transmitter and the receiver to calculate the analog radio frequency signal leaked from the transmitter to the receiver, the interference caused by the leaked analog radio frequency signal to the receiver can be eliminated.

[0030] In one possible implementation, the tag reader includes an antenna, and the receiver and the transmitter are both connected to the antenna; the self-interference elimination circuit also includes: a transceiver port isolation circuit; the method also includes: the transceiver port isolation circuit suppresses the radio frequency signal from coupling the transmitter to the receiver. For a tag reader that uses the same antenna for reception and transmission, a transceiver port isolation circuit can be set at the interface of the antenna, receiver and transmitter to suppress the radio frequency signal from coupling the transmitter to the receiver.

[0031] In a fifth aspect, an RFID tag is provided, comprising a memory for storing a computer program code, wherein the computer program code comprises instructions; a radio frequency circuit for sending and receiving wireless signals; and a processor for executing the above instructions, so that the RFID tag implements the RFID method as described in any possible implementation of the third aspect.

[0032] In a sixth aspect, a tag reader is provided, which includes a memory for storing a computer program code, wherein the computer program code includes instructions; a radio frequency circuit for sending and receiving wireless signals; and a processor for executing the above instructions, so that the tag reader implements the RFID method as described in any possible implementation of the fourth aspect.

[0033] In a seventh aspect, an RFID system is provided, the RFID system comprising the RFID tag described in any possible implementation of the first aspect or the fifth aspect and the tag reader described in any possible implementation of the second aspect or the sixth aspect.

[0034] In an eighth aspect, a computer-readable storage medium is provided, on which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, the RFID method as described in any possible implementation of the third aspect or the fourth aspect is implemented.

[0035] In a ninth aspect, a chip system is provided, the chip system comprising a processor and a memory, wherein instructions are stored in the memory; when the instructions are executed by the processor, the RFID method as described in any possible implementation of the third aspect or the fourth aspect is implemented. The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0036] In a tenth aspect, a computer program product is provided, which, when executed on a computer, implements the RFID method as described in any possible implementation manner in the third aspect or the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Three network architecture diagrams provided for embodiments of the present application;

[0038] Figure 2 A structural diagram of an RFID tag provided in an embodiment of the present application;

[0039] Figure 3 A schematic diagram of a process of determining a modulation signal waveform for an RFID tag provided in an embodiment of the present application;

[0040] Figure 4 Schematic diagrams of several modulation methods provided in embodiments of the present application;

[0041] Figure 5A A structural diagram of a first tag reader provided in an embodiment of the present application;

[0042] Figure 5B A filtering schematic diagram of a bandpass filter provided in an embodiment of the present application;

[0043] Figure 6 A structural diagram of a second tag reader provided in an embodiment of the present application;

[0044] Figure 7 A structural example diagram of an analog self-interference elimination circuit provided in an embodiment of the present application;

[0045] Figure 8 An example of a graphic effect of eliminating self-interference of a tag reader provided in an embodiment of the present application;

[0046] Fig. 9 A structural diagram of a third tag reader provided in an embodiment of the present application;

[0047] Fig.10 A structural diagram of a fourth tag reader provided in an embodiment of the present application;

[0048] Fig.11 A working architecture diagram of a tag reader and an RFID tag provided in an embodiment of the present application;

[0049] Fig.12 A flow chart of an RFID method provided in an embodiment of the present application;

[0050] Fig.13 A flowchart of a receiver processing signal of a tag reader provided in an embodiment of the present application;

[0051] Fig.14 A schematic diagram of the structure of an RFID tag provided in an embodiment of the present application;

[0052] Fig.15 A schematic diagram of the structure of a tag reader provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] To facilitate understanding, the concepts and terms that may appear in this application are explained below.

[0054] RFID tag: also known as electronic tag, smart tag, RFID transponder or RFID data carrier. Usually composed of coupling elements and chips, each RFID tag has a unique electronic code. In some scenarios, RFID tags can be attached to objects to identify the objects.

[0055] Tag reader: Also called a reader, scanner, reader, communicator, or reader / writer (depending on whether the RFID tag can be rewritten wirelessly), etc. Usually used to read (and sometimes write) RFID tag information. For example, a tag reader can be a handheld or fixed device.

[0056] Carrier signal: Carrier signal refers to the RF signal after sound, image and other signals are loaded onto a high-frequency signal of a certain frequency. When there is no sound, image and other signals loaded, the amplitude and phase of the high-frequency signal are usually fixed. After the sound, image and other signals are loaded, the amplitude or phase of the high-frequency signal will change with the change of the amplitude of the sound, image and other signals.

[0057] Square wave signal: The quality of the signal in the circuit system is that the signal can be transmitted from the source to the receiving end without distortion within the required time. We call the signal a square wave signal. An ideal square wave signal has only two values: "high level" and "low level".

[0058] The technical solution in this application is described below in conjunction with the accompanying drawings.

[0059] It can be understood that tag readers can be divided into the following three categories according to the antenna structure: 1) The tag reader includes an antenna for receiving and sending; 2) The tag reader includes a receiving antenna and a transmitting antenna, and the receiving antenna and the transmitting antenna are set at the same location; 3) The tag reader includes a receiving antenna and a transmitting antenna, and the receiving antenna and the transmitting antenna are set at different locations respectively.

[0060] Please refer to Figure 1 , Figure 1 The network architecture applicable to the above three structures is shown. Figure 1 The tag reader 110 shown in (a) includes an antenna 101, which is used for both receiving and transmitting signals. The radio frequency signal transmitted by the antenna 101 will also be received by the antenna 101, thereby interfering with the signal from the RFID tag 120 (i.e., self-interference) that the tag reader 110 demodulates. Figure 1 The tag reader 110 shown in (b) of FIG. 1 includes a receiving antenna 103 and a transmitting antenna 104. The receiving antenna 103 is used to receive signals, and the transmitting antenna 104 is used to transmit signals. The radio frequency signal transmitted by the transmitting antenna 104 will also be received by the receiving antenna 103, so the above-mentioned self-interference problem will also exist. Figure 1 The tag reader 110 shown in (c) includes a receiving antenna 105 and a transmitting antenna 106. The receiving antenna 105 and the transmitting antenna 106 are respectively arranged at different positions. Since the radio frequency signal emitted by the transmitting antenna 106 needs to propagate in space to reach the receiving antenna 105, the self-interference of the tag reader is smaller than that of the structure described in 1) and 2) above. However, if the positions of the receiving antenna 105 and the transmitting antenna 106 are close, the above-mentioned self-interference problem will still exist. Therefore, the solution provided in the embodiment of the present application is applicable to the tag readers of the above three types of structures. And, the solution provided in the embodiment of the present application is applicable to Figure 1 All three network structures shown are applicable.

[0061] The embodiments of the present application provide an RFID tag, a tag reader, and an RFID system consisting of an RFID tag and a tag reader. The RFID system can reduce the impact of the self-interference problem of the tag reader on the identification of the RFID tag and the acquisition of information. The solution provided by the embodiments of the present application can be applied to logistics, transportation, identity recognition, anti-counterfeiting, asset management, food, information statistics, transactions, reference applications or security control and other fields. For example, it is applied to book management, logistics management, water and electricity charges, access control management, shelf management or industrial production line management. The solution provided in this application is not limited to specific application scenarios.

[0062] It should be noted that RFID technology can be divided into active RFID (also known as active RFID), passive RFID and semi-active RFID according to the different power supply methods of RFID tags. Correspondingly, RFID tags can be divided into active RFID tags, passive RFID tags and semi-active RFID tags. The energy for the operation of active RFID tags is provided by a power source (such as a battery). Passive RFID tags obtain energy to temporarily power themselves by receiving radio frequency signals emitted by tag readers and generating induced currents through electromagnetic induction coils to complete information exchange with tag readers. Semi-active RFID tags are provided with a power source (such as a battery), but the power source only powers the internal circuit of the RFID tag when the RFID tag is in a dormant state, and activates the RFID tag when the RFID tag is within the magnetic field range of the tag reader. The energy source for the subsequent processing process after the RFID tag enters the working state is similar to that of the passive RFID tag. This application does not limit the power supply method of the RFID tag.

[0063] like Figure 2 As shown, Figure 2 FIG. 1 shows a structural diagram of an RFID tag provided in an embodiment of the present application. Figure 2 As shown, the RFID tag 120 may include a logic processing unit 201, a rectangular wave generator 202, a first load Z0203, a second load Z1204, a load switch 205, and an antenna 206. The load switch includes a control terminal 2051 and a connection terminal 2052. The logic processing unit 201 is connected to the rectangular wave generator 202. The load switch 205 is used to connect the first load 203 or the second load 204. The rectangular wave generator 202 is connected to the load switch 205 via the control terminal 2051.

[0064] In the embodiment of the present application, the logic processing unit 201 is used to configure the working frequency (such as the first frequency) for the rectangular wave generator 202. And, it is used to input the information bit stream to the rectangular wave generator 202, enable the rectangular wave generator 202, so that the rectangular wave generator 202 converts the information bit stream obtained from the logic processing unit 201 into a square wave signal of the first frequency or into a low level. Among them, the information bit stream input by the logic processing unit 201 to the rectangular wave generator 202 is the information bit stream after being encoded and modulated by the logic processing unit 201. The information bit stream can at least be used to represent the identification information of the RFID tag and / or the information stored in the RFID tag.

[0065] Among some possible structures, such as Figure 2 As shown, the rectangular wave generator 202 may include three ports: a configuration port a, an enable port b, and an output port c. The rectangular wave generator 202 is connected to the logic processing unit 201 through the configuration port a and the enable port b, respectively. The rectangular wave generator 202 is connected to the control end 2051 of the load switch 205 through the output port c. The configuration port a is used to receive the operating frequency configured by the logic processing unit 201 for the rectangular wave generator 202, that is, the first frequency f1. The enable port b is used to receive the information bit stream output by the logic processing unit 201. The output port c is used to output the converted signal (including the square wave signal of the first frequency and / or the continuous low level). More specifically, the output port c is used to transmit the converted signal to the control end 2051 of the load switch 205.

[0066] The conversion of the information bit stream to the square wave signal / low level by the rectangular wave generator 202 (e.g., an oscillator (OSC)) may specifically include: if the information bit stream input from the enable port b indicates a first identifier (e.g., a binary number "1"), the output port c outputs a square wave signal of a first frequency f1 (e.g., 15 MHz), wherein the square wave signal includes a high level (High, H) and a low level (Low, L) alternating at the first frequency; if the information bit stream input from the enable port b indicates a second identifier (e.g., a binary number "0"), the output port c outputs a low level. Alternatively, if the information bit stream input from the enable port b indicates a binary number "0", the output port c outputs a square wave signal of a first frequency f1 (e.g., 15 MHz); if the information bit stream input from the enable port b indicates a binary number "1", the output port c outputs a low level. For example, Figure 3 Signal 1 in FIG. 1 shows the information bit stream “…1101…” input from the enable port b by the logic processing unit 201 to the rectangular wave generator 202. Signal 2 shows the converted signal output from the output port c after signal 1 is processed by the rectangular wave generator 202.

[0067] In the present application, the converted signal outputted from the output port c by the rectangular wave generator 202 is used to control the load switch 205 to connect the first load 203 or the second load 204. So that the antenna 206 is connected to the first load 203 or the second load 204 through the connection end 2052 of the load switch 205. Specifically, when the converted signal obtained by the control end 2051 of the load switch 205 indicates a high level of the first frequency, the connection end 2052 of the load switch 205 connects the first load Z0 203; when the converted signal indicates a low level of the first frequency, the connection end 2052 of the load switch 205 connects the second load Z1 204. When the converted signal indicates a continuous low level, the connection end 2052 of the load switch 205 remains connected to the second load Z1 204 unchanged. Alternatively, when the converted signal obtained by the control terminal 2051 of the load switch 205 indicates a low level of the first frequency, the connection terminal 2052 of the load switch 205 connects the first load Z0 203; when the converted signal indicates a high level of the first frequency, the connection terminal 2052 of the load switch 205 connects the second load Z1 204. When the converted signal indicates a continuous low level, the connection terminal 2052 of the load switch 205 keeps connecting the first load Z0 203 unchanged.

[0068] The resistance difference between Z0 and the load of the antenna is less than a first preset threshold, and the resistance difference between Z1 and the load of the antenna is greater than a second preset threshold. For example, the first preset threshold is 0.1, and the second preset threshold is 10.

[0069] It can be understood that when the external load is equal to or close to the load of the antenna (i.e., the external load matches the load impedance of the antenna), the antenna 206 is in a full reflection state. In this case, the antenna 206 can largely reflect the RF signal from the tag reader 110. When the external load is far different from the load of the antenna (i.e., the external load does not match the load impedance of the antenna), the antenna 206 will less reflect the RF signal from the tag reader 110. For the working principle of the antenna, please refer to the introduction in the conventional technology, which will not be repeated here.

[0070] With the frequency of the radio frequency signal from the tag reader 110 as the second frequency f2, the output port c of the rectangular wave generator 202 outputs the control terminal 2051 of the load switch 205. Figure 3As an example, the square wave signal including the first frequency f1 and the converted signal of the continuous low level shown in the signal 2 in the figure, the load switch 205 controls the connection terminal 2052 to respectively connect Z0→Z1→Z0→Z1→Z0→Z1→Z0→Z1→Z1→Z1→Z1→Z1→Z0→Z1→Z0→Z1 according to the signal 2 through the control terminal 2051. Then, when the connection terminal 2052 of the load switch 205 switches between Z0 and Z1 at the first frequency f1, the antenna 206 sends a modulated signal of the third frequency f3 to the tag reader 110, wherein f3=f1+f2; when the connection terminal 2052 of the load switch 205 is connected to Z1 for a time length greater than the preset time length (such as Figure 2 shown ), a modulation signal of the second frequency f2 is sent to the tag reader 110. Figure 3 As shown, Figure 3 The signal 3 in FIG. 1 shows the radio frequency signal from the tag reader 110. The radio frequency signal is a carrier signal with a frequency of 890 MHz (i.e., the second frequency f2). Assuming that the operating frequency of the rectangular wave generator 202 (i.e., the first frequency f1 is 15 MHz), Figure 3 Signal 4 in FIG. 4 shows a modulated signal sent by antenna 206. The frequency of the modulated signal is 905 MHz (ie, f3) when the information bit stream indicates a binary number "1", and the frequency of the modulated signal is 890 MHz (ie, f2) when the information bit stream indicates a binary number "0".

[0071] It should be noted that Figure 2 As an example of RFID tag structure, although Figure 2 Not shown, the RFID tag may also include other modules such as a power supply, which will not be described in detail here.

[0072] It should be understood that the above Figure 2 The hardware modules included in the RFID tag shown are only exemplary descriptions and do not constitute a limitation to the present application. In fact, Figure 2 The RFID tag shown may also include other hardware modules that have an interactive relationship with the hardware modules illustrated in the figure, which is not specifically limited here.

[0073] It should be noted that Figure 3 Signal 4 in the figure is only an example of binary on-off keying (OOK), also known as binary amplitude shift keying (ASK). The modulation method of the RFID tag provided in the embodiment of the present application can also be phase shift keying (PSK) and frequency shift keying (FSK). Please refer to Figure 4 , Figure 4Several examples of binary modulation waveforms are shown. Among them, binary OOK is a binary code sequence (such as Figure 3 The signal 2 in the signal is used to control the on and off of the sinusoidal carrier. PSK is a modulation technology that uses the carrier phase to represent the input signal information. PSK can include absolute phase shift and relative phase shift. Phase modulation based on the phase of the unmodulated carrier is called absolute phase shift. Taking binary PSK as an example, when the code element is "1", the modulated carrier is in phase with the unmodulated carrier; when the code element is "0", the modulated carrier is anti-phase with the unmodulated carrier; when "1" and "0", the modulated carrier phase difference is 180°. FSK uses the frequency of the carrier to transmit digital information. Taking binary FSK as an example, when the code element is "1", the frequency of the modulated carrier is frequency 1; when the code element is "0", the frequency of the modulated carrier is frequency 2 (different from frequency 1). For a detailed introduction to OOK, PSK and FSK, please refer to the explanations and instructions in conventional technology, which will not be repeated here.

[0074] Please refer to Figure 5A , Figure 5A FIG. 1 shows a structural diagram of a tag reader provided by an embodiment of the present application. Figure 5A As shown, the tag reader 110 may include a logic processing unit 501, a receiver 502, a transmitter 503 and an antenna 504. The logic processing unit 501 is connected to both the receiver 502 and the transmitter 503. Both the receiver 502 and the transmitter 503 are connected to the antenna 504.

[0075] In the embodiment of the present application, the antenna 504 is used for both transmitting and receiving signals. The logic processing unit 501 is used to control the transmitter 503 to transmit a radio frequency signal through the antenna 504. For example, the radio frequency signal is Figure 3 The signal 3 in FIG. 5 is a carrier signal with a frequency of f2. The receiver 502 is used to receive modulated signals from one or more RFID tags through the antenna 504.

[0076] For example, the receiver 502 can receive the Figure 3The signal 4 with a frequency of f3 from the RFID tag 120 shown in FIG. As described above, since the receiver 502 and the transmitter 503 share an antenna, the radio frequency signal transmitted by the antenna 504 will also be received by the antenna 504. In addition, the antenna 504 will also receive the radio frequency signal reflected by the RFID tag 120. That is, the signal received by the antenna 504 and transmitted to the receiver 502 includes two parts, one part is the signal with a frequency of f2 (including a part of the radio frequency signal transmitted by the antenna 504 and received by the antenna 504 and the radio frequency signal reflected by the RFID tag 120), and the other part is the signal with a frequency of f3. For the receiver 502, the signal with a frequency of f2 is an interference signal (hereinafter referred to as a "self-interference signal"). Therefore, the receiver 502 needs to filter out the signal with a frequency of f2 from the signal received by the antenna 504.

[0077] like Figure 5A As shown, the receiver 502 may include a bandpass filter 5021, an envelope detector 5022, and a comparator 5023. The bandpass filter 5021 is connected to the envelope detector 5022, and the envelope detector 5022 is connected to the comparator 5023. The signal received from the antenna 504 will pass through the bandpass filter 5021, the envelope detector 5022, and the comparator 5023 in sequence. Since the frequency of the radio frequency signal with a frequency f2 transmitted by the transmitter 503 through the antenna 504 is different from the frequency of the modulation signal with a frequency f3 from the RFID tag, the bandpass filter 5021 is specifically used to suppress self-interference signals (such as Figure 3 The frequency of the signal f2 shown in FIG3 ) is not included, but the modulated signal (i.e., the first signal) after the frequency conversion from the RFID tag is allowed to pass. For example, the first signal can be Figure 3 The signal 4 with a frequency of f3 shown in . The envelope detector 5022 is used to convert the modulated signal after frequency conversion from the RFID tag in the first signal into an envelope signal. The comparator 5023 is used to compare the envelope signal converted by the envelope detector 5022 with the reference voltage and then output it. For example, if the voltage of the envelope signal is higher than the reference signal, the first identifier (for example, "binary number 1") is output; if the voltage of the envelope signal is lower than the reference signal, the second identifier (for example, binary number "0") is output. Alternatively, if the voltage of the envelope signal is higher than the reference signal, the binary number "0" is output; if the voltage of the envelope signal is lower than the reference signal, the binary number "1" is output.

[0078] Please refer to Figure 5B , Figure 5B A filtering schematic diagram of a bandpass filter is shown. Figure 5BTaking f1 = 15MHz, f2 = 890MHz, and the bandpass filter 5021 as a 902MHz-928MHz filter as an example, the filtering process of the bandpass filter is introduced, such as Figure 5B As shown, the bandpass filter 5021 allows the signal with a frequency of f3 (ie, the modulation signal with a frequency of 905 MHz from the RFID tag) to pass, but filters out the signal with a frequency of f2 (ie, the self-interference signal of the RFID tag).

[0079] It should be noted that Figure 5B The example of a bandpass filter directly filtering out the self-interference signal of the RFID tag is taken. The embodiment of the present application does not limit whether the bandpass filter directly filters the self-interference signal or suppresses the self-interference signal. Among them, the bandpass filter suppresses the self-interference signal to obtain the effect of greatly attenuating the self-interference signal, for example, attenuating 35dB.

[0080] In some embodiments, the tag reader 110 may further include a self-interference elimination circuit for eliminating the signal leaked from the transmitter 503 to the receiver 502 . The self-interference elimination circuit is arranged between the receiver 502 and the transmitter 503 .

[0081] Wherein, the self-interference elimination circuit includes a transceiver port isolation circuit. For example, Figure 6 As shown, the transmit and receive port isolation circuit can be composed of Figure 6 Circulator 505 is composed of a circulator 505 shown in FIG. Circulator 505 includes three ports: port 1 (i.e., the first port), port 2 (i.e., the second port), and port 3 (i.e., the third port). Port 1 is connected to transmitter 503, port 2 is connected to receiver 502, and port 3 is connected to antenna 504. Port 1 and port 2 of circulator 505 provide a certain degree of isolation to reduce the signal from transmitter 503 coupling to receiver 502.

[0082] In some embodiments, Figure 6 As shown, the self-interference elimination circuit may also include an analog self-interference elimination circuit 506. The basic working process of the analog self-interference elimination circuit 506 includes: the analog self-interference elimination circuit 506 samples the analog radio frequency signal leaked from the transmitter 503, and then simulates the radio frequency signal leaked from the transmitter 503. Finally, the simulated radio frequency signal is subtracted from the receiver 502 to reduce the signal coupled from the transmitter 503 to the receiver 502. As an example, please refer to Figure 7 , Figure 7 A structural example diagram of an analog self-interference elimination circuit provided in an embodiment of the present application is shown.

[0083] In some embodiments, the self-interference elimination circuit may use a single-tap delay line to provide isolation, such as 35 dB, between the transmitter 503 and the receiver 502. For the specific principle of the single-tap delay line, reference may be made to the explanation and description in conventional technology, which will not be repeated here.

[0084] pass Figure 6 The transceiver port isolation circuit (i.e., circulator 505) shown in FIG. Figure 7 The analog self-interference cancellation circuit 506 shown in FIG. Figure 5A The self-interference elimination achieved by the receiver 502 of the structure shown can greatly reduce the self-interference problem of the tag reader 110. Figure 8 , Figure 8 An example of the effect diagram of a tag reader self-interference elimination is shown. Figure 8 As shown, assuming that the transmission power of the radio frequency signal transmitted by the transmitter 503 through the antenna is 33dBm, the radio frequency signal reaches the RFID tag 120 after a part of the attenuation due to space loss. The RFID tag 120 reflects the radio frequency signal, which will cause partial loss. Subsequently, the radio frequency signal reflected by the RFID tag 120 is attenuated again due to space loss and reaches the tag reader 110. In order to better avoid the interference of the second frequency signal to the demodulated signal of the tag reader 110, the interference signal can be filtered out by isolating the transceiver port (such as a circulator), simulating self-interference elimination and bandpass filter self-interference elimination.

[0085] It should be noted that Figure 6 The transceiver port isolation circuit (ie, circulator 505) and Figure 7 The analog self-interference elimination circuit 506 shown is only used as an example. The specific working principle and structure of the transceiver port isolation circuit and the analog self-interference elimination circuit are not limited in the present embodiment. Regarding the transceiver port isolation and the analog self-interference elimination, reference can be made to the introduction and description in the conventional technology, which will not be repeated here.

[0086] As mentioned above, the tag reader 110 may also include two antennas: a receiving antenna and a transmitting antenna. Fig. 9 , Fig. 9 A structural diagram of another tag reader provided in an embodiment of the present application is shown.

[0087] like Fig. 9As shown, the tag reader 110 may include a logic processing unit 501, a receiver 502, a transmitter 503, a transmitting antenna 901, and a receiving antenna 902. The logic processing unit 501 is connected to both the receiver 502 and the transmitter 503. The transmitting antenna 901 is connected to the transmitter 503, and the receiving antenna 902 is connected to the receiver 502.

[0088] In the embodiment of the present application, the transmitting antenna 901 is used to transmit a signal from the transmitter 503. The receiving antenna 902 is used to receive a signal and transmit the received signal to the receiver 502 for further processing. In some embodiments, the polarization directions of the transmitting antenna 901 and the receiving antenna 902 are different to ensure sufficient isolation between the transmitting antenna 901 and the receiving antenna 902 to reduce mutual interference.

[0089] The logic processing unit 501 is used to control the transmitter 503 to transmit a radio frequency signal through the transmitting antenna 901. For example, the radio frequency signal is Figure 3 The signal 3 in FIG. 5 is a carrier signal with a frequency of f2. The receiver 502 is used to receive modulated signals from one or more RFID tags through the receiving antenna 902.

[0090] For example, the receiver 502 can receive the Figure 3 The signal 4 with a frequency of f3 from the RFID tag 120 shown in FIG. As described above, when the transmitting antenna 901 and the receiving antenna 902 are arranged at the same location, or when the transmitting antenna 901 and the receiving antenna 902 are arranged at different locations but at a close distance, the radio frequency signal transmitted by the transmitting antenna 901 will also be received by the receiving antenna 902. That is to say, the signal transmitted from the receiving antenna 902 to the receiver 502 also includes two parts, one part is the signal with a frequency of f2, and the other part is the signal with a frequency of f3. For the receiver 502, the signal with a frequency of f2 is an interference signal (more specifically, a self-interference signal). Therefore, the receiver 502 needs to filter out the signal with a frequency of f2 from the signal received by the antenna 504.

[0091] for Fig. 9 For the tag reader 110 of the structure shown in FIG. Fig. 9 As shown, the receiver 502 may also have Figure 5A For the structure of the receiver 502, please refer to the above description. Figure 5A The introduction and description will not be repeated here.

[0092] In some embodiments, Fig. 9The tag reader 110 shown may also include a self-interference elimination circuit for eliminating the signal leaked from the transmitter 503 to the receiver 502. The self-interference elimination circuit is arranged between the receiver 502 and the transmitter 503. More specifically, as shown in FIG. Fig.10 As shown, the self-interference elimination circuit may be an analog self-interference elimination circuit 506. The structure and working principle of the analog self-interference elimination circuit 506 may refer to Figure 7 As well as the above Figure 7 Please refer to the explanations and descriptions in the conventional technology, and no further details will be given here.

[0093] It should be noted that the tag reader 110 in the embodiment of the present application can provide services to multiple RFID tags at the same time. Fig.11 As shown, it is assumed that the tag reader 110 provides services to the first RFID tag and the second RFID tag at the same time. The first RFID tag and the second RFID tag can only have Figure 2 The structure shown. The difference between the first RFID tag and the second RFID tag is that the operating frequencies (i.e., the first frequencies) of the rectangular wave generators in the first RFID tag and the second RFID tag are different. For example, the operating frequency f11 of the first RFID tag is 15 MHz, and the operating frequency f12 of the second RFID tag is 16 MHz. In this case, the signal received by the receiver 502 of the tag reader 110 includes: a modulated signal of the operating frequency f11 from the first RFID tag, a modulated signal of the operating frequency f12 from the second RFID tag, and a self-interference signal of the frequency f2.

[0094] for Fig.11 In the scenario shown, the bandpass filter 5021 first suppresses (e.g., filters) the self-interference signal of the frequency f2, allowing the modulation signal of the operating frequency f11 and the modulation signal of the operating frequency f12 to pass through, and then enters the envelope detector 5022 and the comparator 5023 in turn for post-processing.

[0095] It can be understood that, since the operating frequencies (ie, the first frequency) of the rectangular wave generators in the first RFID tag and the second RFID tag are different, the signals from different RFID tags can be distinguished from the mixed signal by digital filtering at the baseband.

[0096] It should be noted that Fig.11 So Figure 5A The tag reader with the structure shown in the figure is used as an example to introduce the process of the tag reader processing the signals from two RFID tags at the same time, and the structure of the tag reader is not limited. Figure 6 , Fig. 9 or Fig.10The tag reader of the structure shown, or other tag readers of similar structure, can also use the same method to distinguish multiple RFID tags. In addition, the embodiment of the present application does not limit the number of RFID tags that communicate with the tag reader, for example, it can be 3, 4, ...

[0097] The present application also provides an RFID method, which can be applied to a Figure 5A , Figure 6 , Fig. 9 or Fig.10 A tag reader of the structure shown, or a tag reader of other similar structures, and a Figure 2 An RFID tag having the structure shown or a similar structure. Specifically, the RFID tag 120 includes a logic processing unit 201, a rectangular wave generator 202, a first load 203, a second load 204, a load switch 205, a transmitting antenna 901 and a receiving antenna 902. The load switch 205 includes a control terminal 2051 and a connection terminal 2052. The logic processing unit 201 is connected to the rectangular wave generator 202 through a configuration terminal a and an enable terminal b. The output terminal c of the rectangular wave generator 202 is connected to the control terminal 2051 of the load switch 205. Among them, the resistance difference between the first load 203 and the load of the antenna is less than a first preset threshold value (such as 0.1), and the resistance difference between the second load 204 and the load of the antenna is greater than a second preset threshold value (such as 10).

[0098] The following Fig. 9 The tag reader 110 of the structure shown, Figure 2 Taking the RFID tag 120 of the structure shown as an example, the RFID method provided by the embodiment of the present application is specifically introduced.

[0099] like Fig.12 As shown, the RFID method provided in the embodiment of the present application may include steps S1201-S1207:

[0100] S1201 , the logic processing unit 201 of the RFID tag 120 transmits an information bit stream to the rectangular wave generator 202 .

[0101] For example, the information bit stream can be Figure 3 The information bit stream shown in signal 1.

[0102] S1202 : The logic processing unit 201 of the RFID tag 120 instructs the rectangular wave generator 202 to convert the information bit stream into a square wave signal of a first frequency or a low level.

[0103] For example, the first frequency may be Figure 3 f1 shown in .

[0104] S1203 , the rectangular wave generator 202 of the RFID tag 120 converts the first identifier in the received information bit stream into a square wave signal of the first frequency, converts the second identifier in the information bit stream into a low level, and transmits the converted signal to the load switch 205 .

[0105] Specifically, the rectangular wave generator 202 may transmit the converted signal to the control terminal 2051 of the load switch 205 .

[0106] If the information bit stream indicates a first identifier (such as a binary number "1"), the rectangular wave generator 202 outputs a square wave signal of a first frequency; if the information bit stream indicates a second identifier (such as a binary number "0"), the rectangular wave generator 202 outputs a low level. Specifically, the rectangular wave generator 202 outputs a square wave signal of a first frequency including: the rectangular wave generator 202 alternately outputs a high level and a low level according to the first frequency. For example, the converted signal output by the rectangular wave generator 202 may be Figure 3 Alternatively, if the information bit stream indicates a binary number "0", the rectangular wave generator 202 outputs a square wave signal of the first frequency; if the information bit stream indicates a binary number "0", the rectangular wave generator 202 outputs a low level.

[0107] S1204 , the load switch 205 of the RFID tag 120 turns on the first load 203 or the second load 204 according to the converted signal received from the rectangular wave generator 202 .

[0108] Specifically, the load switch 205 switches on the first load 203 or the second load 204 through the connection terminal 2052 according to the converted signal received from the rectangular wave generator 202 .

[0109] If the converted signal indicates a high level of the first frequency, the connection end 2052 of the load switch 205 connects the first load 203. If the converted signal indicates a low level of the first frequency, the connection end 2052 of the load switch 205 connects the second load 204. If the converted signal indicates a continuous low level, the second load 204 remains connected.

[0110] S1205 , the antenna 206 of the RFID tag 120 sends a modulated signal to the tag reader 110 according to the situation that the load switch 205 turns on the first load 203 and the second load 204 .

[0111] Specifically, assuming that the frequency of the radio frequency signal received by the antenna 206 from the tag reader 110 is the second frequency f2, and the operating frequency of the rectangular wave generator 202 is the first frequency f1, if the load switch 205 switches between the first load 203 and the second load 204 at the first frequency f1, the antenna 206 sends a modulation signal of the third frequency f3 to the tag reader 110. If the load switch 205 continues to connect the second load 204 for a time period greater than a preset time period, the antenna 206 sends a modulation signal of the second frequency f2 to the tag reader 110. Wherein, f3=f1+f2.

[0112] S1206. The receiving antenna 902 of the tag reader 110 receives the signal.

[0113] The signal received by the receiving antenna 902 may at least include: a radio frequency signal of the second frequency f2 from the transmitting antenna 901, and a first signal. The first signal is one or more modulated signals from one or more RFID tags 120. The frequencies of the one or more modulated signals are different. For example, the frequency of the modulated signal from the first RFID tag is 905 MHz, and the frequency of the modulated signal from the second RFID tag is 906 MHz.

[0114] S1207 . The receiver 502 of the tag reader 110 processes the signal received by the antenna 902 .

[0115] In the embodiments of the present application, Fig.13 As shown, the above step S1207 may include the following steps S1301-S1303:

[0116] S1301. The bandpass filter 5021 of the receiver 502 suppresses the radio frequency signal of the second frequency and allows the first signal of the third frequency to pass.

[0117] Specifically, the bandpass filter 5021 may have Figure 5A The bandwidth of the bandpass filter 5021 can be set to allow the first signal (i.e., the modulated signal of the third frequency f3) to pass through, but suppress the RF signal of the second frequency f2. For example, the bandpass filter 5021 can be used Figure 5B Filtering is performed using the filtering method shown.

[0118] S1302 : The envelope detector 5022 of the receiver 502 converts one or more modulation signals in the first signal transmitted from the bandpass filter 5021 into envelope signals respectively.

[0119] S1303. The comparator 5023 of the receiver 502 distinguishes one or more RFID tags that send out modulated signals according to the envelope signal.

[0120] Regarding the working principles and specific working processes of the above steps S1201-S1207, and each execution entity in the above steps S1301-S1303 (such as the logic processing unit 201, the rectangular wave generator 202, the load switch 205, the antenna 206, the receiving antenna 902, the bandpass filter 5021 in the receiver 502, the envelope detector 5022 or the comparator 5023), please refer to the introduction and description above and will not be repeated here.

[0121] It is understandable that, in order to implement the functions of any of the above-mentioned embodiments, the RFID tag 120 or the tag reader 110 includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0122] The embodiment of the present application can divide the RFID tag 120 or the tag reader 110 into functional modules. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0123] For example, when the functional modules are divided in an integrated manner, Fig.14 , which is a structural block diagram of an RFID tag 120 provided in an embodiment of the present application. The RFID tag 120 may include a memory 1410 , a radio frequency circuit 1420 , and a processor 1430 .

[0124] The memory 1410 may store computer program code, which includes instructions for implementing the RFID method provided in the embodiment of the present application. And / or store other relevant information in the technology described herein. The radio frequency circuit 1420 is used to support the RFID tag 120 to perform the above step S1205, and / or other processes of the technology described herein. The processor 1430 is used to support the RFID tag 120 to perform the above steps S1201, S1202, S1203 or S1204, and / or other processes of the technology described herein.

[0125] like Fig.15 , which is a structural block diagram of a tag reader 110 provided in an embodiment of the present application. The tag reader 110 may include a memory 1510 , a radio frequency circuit 1520 , and a processor 1530 .

[0126] The memory 1510 may store computer program code, which includes instructions for implementing the RFID method provided in the embodiment of the present application. And / or store other relevant information in the technology described herein. The radio frequency circuit 1520 is used to support the tag reader 110 to perform the above step S1206, and / or other processes of the technology described herein. The processor 1530 is used to support the tag reader 110 to perform the above steps S1207, S1301, SS1302 or S1303, and / or other processes of the technology described herein.

[0127] Typically, the RF circuit 1420 and / or RF circuit 1520 include, but are not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, etc. In addition, the RF circuit can also communicate with other devices via wireless communication. The wireless communication can use any communication standard or protocol, including but not limited to Global System for Mobile Communications, General Packet Radio Service, Code Division Multiple Access, Wideband Code Division Multiple Access, Long Term Evolution, email, short message service, etc.

[0128] In an optional manner, when data transmission is implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is implemented in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive (SSD)), etc.

[0129] The steps of the method or algorithm described in conjunction with the embodiments of the present application can be implemented in a hardware manner, or can be implemented by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a detection device. Of course, the processor and the storage medium can also be present in the detection device as discrete components.

[0130] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0131] In an optional manner, the present application provides a chip system, which includes a processor and a memory, wherein instructions are stored in the memory; when the instructions are executed by the processor, the RFID method in any possible implementation manner provided by the present application is implemented. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0132] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0133] The units described as separate components may or may not be physically separated, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0134] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0135] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

[0136] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A radio frequency identification (RFID) tag, characterized in that: The RFID tag includes: a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch includes a control end and a connection end; The logic processing unit is connected to the rectangular wave generator, and the logic processing unit is used to transmit an information bit stream to the rectangular wave generator, and instruct the rectangular wave generator to convert the information bit stream into a square wave signal of a first frequency or a low level; The rectangular wave generator is connected to the control end of the load switch; the rectangular wave generator is used to receive the information bit stream, convert the first identifier in the information bit stream into a square wave signal of a first frequency, convert the second identifier in the information bit stream into a low level, and transmit the converted signal to the control end of the load switch; wherein the converted signal is used to control the connection end of the load switch to connect the first load or the second load, so that the antenna is connected to the first load or the second load through the connection end of the load switch; The load switch is used to connect the first load or the second load through the connection end according to the converted signal; the antenna is used to send a modulated signal to the tag reader according to the situation that the load switch connects the first load and the second load; The resistance difference between the first load and the load of the antenna is smaller than a first preset threshold, and the resistance difference between the second load and the load of the antenna is larger than a second preset threshold.

2. The RFID tag according to claim 1, characterized in that: The rectangular wave generator comprises: a configuration port, an enable port and an output port; the rectangular wave generator is connected to the logic processing unit through the configuration port and the enable port respectively; the rectangular wave generator is connected to the control end of the load switch through the output port; The configuration port is used to receive the first frequency configured by the logic processing unit; the enable port is used to receive the information bit stream output by the logic processing unit; and the output port is used to transmit the converted signal to the control end of the load switch.

3. The RFID tag according to claim 1, characterized in that: The first identifier is a binary number "1", and the second identifier is a binary number "0"; or, the first identifier is a binary number "0", and the second identifier is a binary number "1".

4. The RFID tag according to any one of claims 1 to 3, characterized in that: The load switch is specifically used for: When the converted signal indicates a high level of the first frequency, the first load is turned on; when the square wave signal indicates a low level of the first frequency, the second load is turned on; when the converted signal indicates a continuous low level, the second load remains turned on; or, When the converted signal indicates a low level of the first frequency, the first load is turned on; when the square wave signal indicates a high level of the first frequency, the second load is turned on; when the converted signal indicates a continuous low level, the first load remains turned on.

5. The RFID tag according to any one of claims 1 to 3, characterized in that: The antenna is specifically used for: receiving a radio frequency signal from the tag reader, wherein the frequency of the radio frequency signal is a second frequency; and When the load switch switches between the first load and the second load at the first frequency, a modulation signal of a third frequency is sent to the tag reader; when the load switch switches on the second load for a duration greater than a preset duration, a modulation signal of a second frequency is sent to the tag reader; Wherein, the third frequency=first frequency+second frequency.

6. A tag reader, characterized in that: The tag reader comprises: a logic processing unit, a receiver, a transmitter and at least one antenna; the logic processing unit is connected to both the receiver and the transmitter; the receiver and the transmitter are connected to the at least one antenna; The receiver includes: a bandpass filter, an envelope detector and a comparator, wherein the bandpass filter is connected to the envelope detector, and the envelope detector is connected to the comparator; the bandpass filter is used to suppress the radio frequency signal from the transmitter and allow the first signal to pass; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector is used to convert one or more modulated signals in the first signal into envelope signals respectively; the comparator is used to demodulate according to the envelope signal and a preset reference voltage to obtain an information bit stream from the one or more RFID tags; The frequencies of the one or more modulation signals are all different.

7. The tag reader according to claim 6, characterized in that: The tag reader also includes: a self-interference elimination circuit; the self-interference elimination circuit is arranged between the transmitter and the receiver; the self-interference elimination circuit includes an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between the transmitter and the receiver; the analog self-interference elimination circuit is used to eliminate the analog radio frequency signal leaked from the transmitter to the receiver.

8. The tag reader according to claim 7, characterized in that: The tag reader comprises a receiving antenna and a transmitting antenna; the receiver is connected to the receiving antenna, and the transmitter is connected to the transmitting antenna.

9. The tag reader according to claim 8, characterized in that: The receiving antenna and the transmitting antenna have different polarization directions.

10. The tag reader according to claim 7, characterized in that: The tag reader comprises an antenna, and the receiver and the transmitter are both connected to the antenna.

11. The tag reader according to claim 7 or 10, characterized in that: The self-interference elimination circuit further includes: a transceiver port isolation circuit; the transceiver port isolation circuit is used to suppress the radio frequency signal of the transmitter coupling to the receiver.

12. The tag reader according to claim 11, characterized in that: The transceiver port isolation circuit includes a circulator; the circulator includes a first port, a second port and a third port, the first port is connected to the transmitter, the second port is connected to the receiver, and the third port is connected to the antenna.

13. The tag reader according to any one of claims 6-10 and 12, characterized in that: The one or more modulation signals include a modulation signal of a third frequency f3; The bandpass filter is specifically used to: suppress the radio frequency signal from the transmitter and allow the modulated signal of the third frequency f3 to pass; The envelope detector is specifically used to: convert the modulation signal of the third frequency f3 into an envelope signal; The comparator is specifically used for: demodulating according to the envelope signal and a preset reference voltage to obtain an information bit stream from the RFID tag that emits the modulation signal of the third frequency f3.

14. A radio frequency identification (RFID) method, characterized in that: The method is applied to an RFID tag, which includes: a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch includes a control end and a connection end, the logic processing unit is connected to the rectangular wave generator, and the rectangular wave generator is connected to the control end of the load switch; the resistance difference between the first load and the load of the antenna is less than a first preset threshold, and the resistance difference between the second load and the load of the antenna is greater than a second preset threshold; the method includes: The logic processing unit transmits the information bit stream to the rectangular wave generator, and instructs the rectangular wave generator to convert the information bit stream into a square wave signal of a first frequency or a low level; The rectangular wave generator receives the information bit stream, converts the first identifier in the information bit stream into a square wave signal of a first frequency, converts the second identifier in the information bit stream into a low level, and transmits the converted signal to the control end of the load switch; wherein the converted signal is used to control the connection end of the load switch to connect the first load or the second load, so that the antenna is connected to the first load or the second load through the connection end of the load switch; The load switch connects the first load or the second load through the connection end according to the converted signal; The antenna sends a modulated signal to the tag reader according to a condition that the load switch turns on the first load and the second load.

15. The method according to claim 14, characterized in that The load switch connects the first load or the second load through the connection end according to the converted signal, specifically comprising: When the converted signal indicates a high level of the first frequency, the load switch turns on the first load through the connection end; when the square wave signal indicates a low level of the first frequency, the load switch turns on the second load through the connection end; when the converted signal indicates a continuous low level, the load switch keeps turning on the second load through the connection end; or, When the converted signal indicates a low level of the first frequency, the load switch connects the first load through the connection end; when the square wave signal indicates a high level of the first frequency, the load switch connects the second load through the connection end; when the converted signal indicates a continuous low level, the load switch keeps connecting the first load through the connection end.

16. The method according to claim 15, characterized in that The first identifier is a binary number "1", and the second identifier is a binary number "0"; or, the first identifier is a binary number "0", and the second identifier is a binary number "1".

17. The method according to any one of claims 14 to 16, characterized in that: The antenna sends a modulated signal to the tag reader according to the condition that the load switch turns on the first load and the second load, specifically including: The antenna receives a radio frequency signal from the tag reader, wherein the frequency of the radio frequency signal is a second frequency; If the load switch switches between the first load and the second load at the first frequency, the antenna sends a modulation signal of a third frequency to the tag reader; if the load switch switches on the first load for a duration greater than a preset duration, the antenna sends a modulation signal of a second frequency to the tag reader; Wherein, the third frequency=first frequency+second frequency.

18. A radio frequency identification (RFID) method, characterized in that: The method is applied to a tag reader, which includes: a logic processing unit, a receiver, a transmitter and at least one antenna; the receiver includes: a bandpass filter, an envelope detector and a comparator, the bandpass filter is connected to the envelope detector, and the envelope detector is connected to the comparator; the method includes: The bandpass filter suppresses the radio frequency signal from the transmitter and allows a first signal to pass; the first signal is one or more modulated signals from one or more RFID tags; The envelope detector converts one or more modulation signals in the first signal into envelope signals respectively; The comparator demodulates the envelope signal and a preset reference voltage to obtain an information bit stream from the one or more RFID tags; The frequencies of the one or more modulation signals are all different.

19. The method according to claim 18, characterized in that The tag reader further includes: a self-interference elimination circuit; the self-interference elimination circuit is arranged between the transmitter and the receiver; the self-interference elimination circuit includes an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between the transmitter and the receiver; the method further includes: The analog self-interference cancellation circuit cancels analog radio frequency signals leaking from the transmitter to the receiver.

20. The method according to claim 19, characterized in that The tag reader includes an antenna, and the receiver and the transmitter are both connected to the antenna; The self-interference elimination circuit further includes: a transceiver port isolation circuit; and the method further includes: The transceiver port isolation circuit suppresses the radio frequency signal that is coupled from the transmitter to the receiver.

Images