Reflection amplification circuit, device, method and electronic tag

Abstract

The application discloses a reflection amplification circuit, device, method and electronic tag. The received signal is coupled through a directional coupler and a radio frequency amplifier, and then the coupled signal is amplified, and the coupled and amplified signal is transmitted through a radio frequency switch. The radio frequency amplifier makes the signal amplification more stable, and the transmission distance of the amplified signal is farther, greatly increasing the limit communication distance. The received signal is transmitted to a downstream receiving port, which not only retains the original signal, but also solves the technical problems of unstable signal amplification and short limit communication distance in the prior art. The technical effect of stably amplifying the signal and improving the limit communication distance under the condition of retaining the original signal is achieved, and the use scene is expanded.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of radio frequency identification technology, in particular to a reflection amplification circuit, device, method and electronic tag. BACKGROUND

[0002] Wireless radio frequency identification, namely radio frequency identification technology (RFID), is a kind of automatic identification technology, which realizes non-contact two-way data communication through wireless radio frequency, and realizes reading and writing of recording media (electronic tag or radio frequency card) through wireless radio frequency, so as to achieve the purpose of identification and data exchange, and it is considered as one of the most potential information technologies in the 21st century.

[0003] Nowadays, electronic tags are more and more widely used in the Internet of Things, and the direct communication mode between the communication base station and the electronic tag has become one of the popular research and application directions. Compared with the communication mode between the ordinary reader and the tag, in the communication mode between the base station reader and the tag, the communication distance is farther, the energy obtained by the tag is smaller, and the signal returned by the tag to the base station reader is weaker. Therefore, if the electronic tag still uses the ordinary backscattering scheme, it cannot meet the distance requirement of the communication between the base station reader and the tag, and the signal must be amplified in some way when the tag returns the signal, so that the base station reader can receive the signal with sufficient signal-to-noise ratio at hundreds of meters away.

[0004] At present, the most commonly used scheme of the reflection amplifier is to use a negative resistance device, so that the reflection coefficient of the signal becomes greater than 1. However, the existing negative resistance device lacks stability and consistency, so that the reflected power changes sharply with the change of environmental temperature, process deviation and bias condition. SUMMARY

[0005] The embodiment of the present application provides a reflection amplification circuit to realize the technical effect of stable amplification of the signal to improve the limit communication distance under the condition of preserving the original signal.

[0006] In a first aspect, the embodiment of the present application provides a reflection amplification circuit, which comprises a directional coupler, a radio frequency amplifier and a radio frequency switch; the directional coupler is connected with an uplink input end, the directional coupler is also connected with the radio frequency amplifier, the radio frequency amplifier is also connected with the radio frequency switch, and the radio frequency switch is also connected with the directional coupler and a downlink receiving end;

[0007] The directional coupler is used for coupling the signal sent by the uplink input end to the radio frequency switch to obtain a coupling signal, and sending the coupling signal to the radio frequency amplifier;

[0008] The radio frequency amplifier is configured to receive the coupling signal and send the amplified coupling signal to the radio frequency switch.

[0009] The radio frequency switch is configured to, when the directional coupler and the downlink receiving end are turned on, receive the signal sent by the uplink input end through the directional coupler and forward the signal to the downlink receiving end; and when the directional coupler and the radio frequency amplifier are turned on, receive the signal amplified by the radio frequency amplifier and send the signal to the uplink input end through the directional coupler.

[0010] Preferably, the antenna and a matching network are further included; the antenna is connected to the matching network, and the matching network is further connected to the uplink input end.

[0011] The antenna is configured to transmit and receive signals.

[0012] The matching network is configured to perform impedance matching on the antenna and suppress interference signals outside the working frequency band.

[0013] Preferably, the matching network includes a first capacitor, a second capacitor and a first inductor.

[0014] One end of the first inductor is connected to the antenna, the other end of the first inductor is connected to the uplink input end, one end of the first inductor is further connected to one end of the first capacitor, the other end of the first capacitor is grounded, the other end of the first capacitor is further connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

[0015] Preferably, a filter is further installed between the directional coupler and the radio frequency switch, the filter is a surface acoustic wave filter, and the filter is configured to filter out noise outside the working frequency band.

[0016] Preferably, a transceiving switching signal end and a digital baseband modulation signal end are further included; the transceiving switching signal end is connected to the radio frequency switch, and the digital baseband modulation signal end is connected to the radio frequency amplifier.

[0017] The transceiving switching signal end is configured to provide the radio frequency switch with a transceiving switching signal.

[0018] The radio frequency switch is further configured to turn on the directional coupler and the downlink receiving end or the directional coupler and the radio frequency amplifier according to the transceiving switching signal.

[0019] The digital baseband modulation signal end is configured to send a digital baseband modulation signal to the radio frequency amplifier.

[0020] Preferably, a first resistor is further included.

[0021] One end of the first resistor is connected with an isolation end of the directional coupler, the other end of the first resistor is grounded, a through end of the directional coupler is connected with one end of the filter, the other end of the filter is connected with a common end of the radio frequency switch, a control end of the radio frequency switch is connected with the transceiving signal switching signal end, a normally closed end of the radio frequency switch is connected with the downlink receiving end, a normally open end of the radio frequency switch is connected with an output end of the radio frequency amplifier, a power supply end of the radio frequency amplifier is connected with a power supply, a grounding end of the radio frequency amplifier is grounded, a co-directional input end of the radio frequency amplifier is connected with the digital baseband modulation signal end, a reverse input end of the radio frequency amplifier is connected with a coupling end of the directional coupler, and an input end of the directional coupler is connected with the uplink input end.

[0022] The application further provides a reflection amplifying device, which comprises the reflection amplifying circuit.

[0023] Preferably, the reflection amplifying device is further connected with a downlink receiving circuit through the downlink receiving end, and the downlink receiving circuit is used for receiving signals transmitted by the reflection amplifying device to the downlink receiving end.

[0024] The application further provides a reflection amplifying method, which specifically comprises the following steps.

[0025] The directional coupler couples signals transmitted by the uplink input end to the radio frequency switch to obtain a coupling signal, and transmits the coupling signal to the radio frequency amplifier.

[0026] The radio frequency amplifier receives the coupling signal, amplifies the coupling signal, and transmits the amplified coupling signal to the radio frequency switch.

[0027] When the radio frequency switch is turned on between the directional coupler and the downlink receiving end, the radio frequency switch receives signals transmitted by the uplink input end through the directional coupler, and transmits the signals to the downlink receiving end; when the radio frequency switch is turned on between the directional coupler and the radio frequency amplifier, the radio frequency switch receives signals amplified by the radio frequency amplifier, and transmits the signals to the uplink input end through the directional coupler.

[0028] The application further provides an electronic tag, which comprises the reflection amplifying device or applies the reflection amplifying method.

[0029] The application couples the received signal through the directional coupler and the radio frequency amplifier, then amplifies the coupled signal, and transmits the coupled and amplified signal through the radio frequency switch, so that the signal amplification is more stable, the transmission distance of the amplified signal is farther, the limit communication distance is greatly increased, and the received signal is transmitted to the downlink receiving port, which not only retains the original signal, but also solves the technical problems of unstable signal amplification and short limit communication distance in the prior art, and achieves the technical effects of stable signal amplification and improved limit communication distance under the condition of retaining the original signal. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a functional module diagram of an embodiment of the task automatic configuration circuit of the application;

[0031] Figure 2 is a functional module diagram of another embodiment of the task automatic configuration circuit of the application;

[0032] Figure 3 is a circuit schematic diagram of another embodiment of the task automatic configuration circuit of the application;

[0033] Figure 4 is a flowchart of an embodiment of the task automatic configuration method of the application. DETAILED DESCRIPTION

[0034] The application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the application, and not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, not all the structures.

[0035] Figure 1 A functional module diagram of a reflection amplification circuit provided for an embodiment of the application, comprising a directional coupler, a radio frequency amplifier and a radio frequency switch;The directional coupler is connected with an uplink input end, the directional coupler is also connected with the radio frequency amplifier, the radio frequency amplifier is also connected with the radio frequency switch, and the radio frequency switch is also connected with the directional coupler and a downlink receiving end;

[0036] The directional coupler is used to couple the signal transmitted from the uplink input end to the radio frequency switch to obtain a coupled signal, and transmit the coupled signal to the radio frequency amplifier;

[0037] The radio frequency amplifier is used to receive the coupled signal, and transmit the coupled signal after amplification to the radio frequency switch;

[0038] The radio frequency switch is used for receiving the signal transmitted by the uplink input end through the directional coupler and forwarding to the downlink receiving end when the directional coupler is connected with the downlink receiving end; and receiving the signal amplified by the radio frequency amplifier and transmitting to the uplink input end through the directional coupler when the directional coupler is connected with the radio frequency amplifier.

[0039] It is easy to understand that the power of the signal will be attenuated after being coupled when passing through the directional coupler, and the line loss in the directional coupler also has a certain attenuation. However, the existing technical problem is that when the input signal not passing through the directional coupler is directly returned to the base station without amplification, the base station cannot stably receive the returned signal. The signal power attenuation mainly occurs in the wireless transmission stage, and the attenuation caused by wired transmission and directional coupling is small. Moreover, the attenuation can be compensated by the signal amplification of the radio frequency amplifier, and even the signal power can be greatly strengthened. The consistency of the coupled signal and the input signal is high, and since the wireless transmission signal mostly has high redundancy, the coupled signal contains complete information of the input signal.

[0040] It should be noted that the gain of the radio frequency amplifier needs to satisfy the attenuation of the sum of the coupling degree, the isolation degree, the radio frequency switch and the filter, otherwise self-oscillation will be caused. Since the consistency of the coupled signal and the input signal is high, the coupled signal can be returned to the uplink input end. Since the power intensity of the coupled signal is smaller than that of the input signal, the power intensity of the coupled signal cannot meet the demand in the case that the power intensity of the input signal cannot meet the demand. Therefore, amplification is needed. After amplification by the radio frequency amplifier, the signal is transmitted to the radio frequency switch.

[0041] It is worth emphasizing that the radio frequency switch can switch the connection of the directional coupler and the downlink receiving end or the connection of the directional coupler and the radio frequency amplifier. When the amplified coupled signal needs to be transmitted, the connection of the directional coupler and the radio frequency amplifier is switched. At this time, the amplified coupled signal is reversely transmitted to the uplink input end through the through line of the directional coupler. When the signal needs to be received, the connection of the directional coupler and the downlink receiving end is switched. The signal transmitted by the uplink input end is directly transmitted to the downlink receiving end through the through line of the directional coupler and the radio frequency switch, thereby completing the reception of data.

[0042] The technical scheme of the embodiment realizes the transmission and reception of the signal by switching the transmission state and the reception state of the radio frequency switch, and couples the input signal through the directional coupler, so that the input signal can be retained after the coupled signal is transmitted. Moreover, the technical problem of unstable signal amplification and short limit communication distance in the prior art is solved by amplifying the coupled signal, thereby achieving the technical effects of stable signal amplification and improved limit communication distance.

[0043] Referring to Figure 2 The reflection amplification circuit further comprises an antenna and a matching network; the antenna is connected with the matching network, and the matching network is further connected with the uplink input end;

[0044] The antenna is used for transmitting and receiving signals.

[0045] The matching network is used for impedance matching of the antenna and suppression of interference signals outside the working frequency band.

[0046] It is easy to understand that the tag antenna enables most of the signal power to be transmitted to the directional coupler through the uplink input end for coupling and transmission to the downlink receiving end through the matching network. The antenna and the matching network need to be adjusted according to the wireless frequency band transmitted by the reader. In this embodiment, the reader is a base station reader, the designed transmission distance is 100 meters, the transmission power of the base station reader is usually 36dbm, and the normal attenuation of 100 meters is 86db. Therefore, the antenna and the matching network designed for the working frequency band of the base station reader can realize a receiving power of-50dbm.

[0047] Referring to Figure 3 The matching network comprises a first capacitor, a second capacitor and a first inductor.

[0048] One end of the first inductor is connected with the antenna, the other end of the first inductor is connected with the uplink input end, one end of the first inductor is further connected with one end of the first capacitor, the other end of the first capacitor is grounded, the other end of the first capacitor is further connected with one end of the second capacitor, and the other end of the second capacitor is grounded.

[0049] It should be noted that the main problem solved by the matching network is that the source impedance and the input impedance are not conjugate. Therefore, the matching network realizes conjugation through the network to minimize the loss of power in transmission, so as to realize the conjugation of the antenna receiving the downlink signal transmitted by the base station. The implementation is not unique, and the matching network disclosed in this embodiment is only one of them.

[0050] Specifically, a filter is further installed between the directional coupler and the radio frequency switch, the filter is a surface acoustic wave filter, and is used for filtering noise outside the working frequency band.

[0051] It is worth emphasizing that the selection of the filter is determined by the communication link requirement. In the case of communication between the base station and the tag, the carrier frequency is about 700M-900M, and the out-of-band noise interference is large. Generally, a surface acoustic wave filter is selected, and the frequency selection characteristic is good.

[0052] Specifically, the transceiver switching signal end and the digital baseband modulation signal end are further included; the transceiver switching signal end is connected with the radio frequency switch, and the digital baseband modulation signal end is connected with the radio frequency amplifier;

[0053] The transceiver switching signal end is used for providing the transceiver switching signal for the radio frequency switch.

[0054] The radio frequency switch is further used for turning on the directional coupler and the downlink receiving end or the directional coupler and the radio frequency amplifier according to the transceiver switching signal.

[0055] The data baseband modulation signal end is used for sending the digital baseband modulation signal to the radio frequency amplifier.

[0056] It should be noted that the tag works in a half-duplex mode, and does not send uplink information when receiving downlink information, and does not receive downlink information when sending uplink information. Therefore, the digital control logic is as follows: when the tag is powered on, the transceiver switching signal end switches the radio frequency switch to receive downlink, and after receiving the downlink information, the transceiver switching signal end automatically switches the radio frequency switch to uplink, and at the same time, the digital processing module connected with the downlink receiving end parses the downlink information and executes the instruction operation in the downlink information, and then sends the signal to the radio frequency amplifier through the digital baseband modulation signal end, and the amplified signal is sent to the uplink through the matching network and the antenna, and then the switching signal end switches the radio frequency switch to receive downlink, and the above process is repeated.

[0057] It should be emphasized that the digital baseband modulation signal controls the gain of the radio frequency amplifier, and when the modulation signal is low, the gain of the radio frequency amplifier is low, and when the modulation signal is high, the gain of the radio frequency amplifier is high; for example, in the above example, when the power of the received signal is-50dbm, the gain reaches 20db, and the reflected power is-30dbm, and after 100 meters of path loss, the base station reader obtains-116dbm of return signal power, and the receiving sensitivity of the base station reader is usually above-120dbm, the communication link is established, and the designed transmission distance of 100 meters is reached, and the designed gain needs to reach 20db, in this embodiment, the coupling degree of the directional coupler is set to 10db, and the isolation degree is > 30db, and the gain of the radio frequency amplifier is selected to be 30db.

[0058] Specifically, the first resistor is further included.

[0059] One end of the first resistor is connected with the isolation end of the directional coupler, the other end of the first resistor is grounded, the through end of the directional coupler is connected with one end of the filter, the other end of the filter is connected with the common end of the radio frequency switch, the control end of the radio frequency switch is connected with the transceiving signal switching signal end, the normally closed end of the radio frequency switch is connected with the downlink receiving end, the normally open end of the radio frequency switch is connected with the output end of the radio frequency amplifier, the power supply end of the radio frequency amplifier is connected with a power supply, the ground end of the radio frequency amplifier is grounded, the co-directional input end of the radio frequency amplifier is connected with the digital baseband modulation signal end, the reverse input end of the radio frequency amplifier is connected with the coupling end of the directional coupler, and the input end of the directional coupler is connected with the uplink input end.

[0060] It is easy to understand that the radio frequency switch is controlled by the control end signal to control the on-off of the common end and the normally closed end or the normally open end, and the circuit implementation of the radio frequency amplifier is not unique, and the gain of the radio frequency amplifier needs to meet the needs of the reflection amplification gain, and at the same time, it is ensured that the reflection loop does not cause self-oscillation.

[0061] The embodiment discloses specific circuits, improves the technical solution, reduces the signal power loss through the surface acoustic wave filter, filters out noise outside the working frequency band, improves the purity of the signal, and maximizes the power of the received signal through the antenna and the matching network. The state of signal receiving and signal sending is switched through the transceiving switching signal end, and the gain of the radio frequency amplifier is controlled through the digital baseband modulation signal end, so that the output power of the return signal is further improved, the transmission distance of the return signal is improved, the design needs are met, and the use scenarios are expanded.

[0062] The application further provides a reflection amplification device.

[0063] The reflection amplification device provided by the embodiment of the application can execute the reflection amplification circuit method provided by any embodiment of the application, has the function modules and beneficial effects corresponding to the execution method, and details are not repeated here.

[0064] Specifically, the reflection amplification device is further connected with a downlink receiving circuit through the downlink receiving end, and the downlink receiving circuit is used for receiving the signal transmitted by the reflection amplification device to the downlink receiving end.

[0065] It should be noted that the active tag generally in communication with the base station is applied to the sensing positioning system, the base station receives the coded radio frequency signal from the tag through the radio frequency transceiver, decodes the authentication identification information of the tag, transmits the authentication identification information and other related information on the tag to the upper computer to realize the tracking of the tag, the base station can write data or change parameters in the electronic tag, at this time, the downlink receiving circuit of the electronic tag needs to process the information transmitted by the base station, and according to the processing result, the operation of data writing or parameter changing is executed.

[0066] With reference to Figure 4 The application further provides a reflection amplification method, which specifically comprises the following steps:

[0067] The directional coupler couples the signal transmitted by the uplink input end to the radio frequency switch to obtain a coupling signal, and transmits the coupling signal to the radio frequency amplifier;

[0068] The radio frequency amplifier receives the coupling signal, amplifies the coupling signal, and transmits the amplified coupling signal to the radio frequency switch;

[0069] When the radio frequency switch is turned on between the directional coupler and the downlink receiving end, the signal transmitted by the uplink input end through the directional coupler is received and forwarded to the downlink receiving end; when the radio frequency switch is turned on between the directional coupler and the radio frequency amplifier, the signal amplified by the radio frequency amplifier is received and transmitted to the uplink input end through the directional coupler.

[0070] Of course, the reflection amplification method provided by the embodiment of the application has the corresponding functional modules and beneficial effects of the above-mentioned circuit, which will not be repeated here.

[0071] The application further provides an electronic tag, which comprises the reflection amplification device described above, or the reflection amplification method described above is applied to the electronic tag.

[0072] Of course, the electronic tag provided by the embodiment of the application has the corresponding functional modules and beneficial effects of the above-mentioned circuit and method, which will not be repeated here.

[0073] Through the above description of the embodiments, those skilled in the art can clearly understand that the present application can be realized by means of software and necessary universal hardware, and of course can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product in essence or in the form of a part of the prior art that makes a contribution. The computer software product can be stored in a computer readable storage medium, such as a floppy disk, a read-only memory (ROM), a random access memory (RAM), a FLASH, a hard disk, or an optical disk, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present application.

[0074] It is worth noting that in the above embodiments of the search device, each unit and module included is only divided according to functional logic, but is not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific names of each functional unit are only for easy mutual differentiation, and do not limit the protection scope of the present application.

[0075] Note that the above are only preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A reflection amplification circuit, characterized by, The application relates to a radio frequency (RF) transceiver, which comprises a directional coupler, an RF amplifier and an RF switch; the directional coupler is connected with an uplink input end; the directional coupler is also connected with the RF amplifier; the RF amplifier is also connected with the RF switch; the RF switch is also connected with the directional coupler and a downlink receiving end; wherein, The directional coupler is used for coupling a signal sent by the uplink input end to the RF switch to obtain a coupling signal, and sending the coupling signal to the RF amplifier; The RF amplifier is used for receiving the coupling signal and sending the amplified coupling signal to the RF switch; The RF switch is used for receiving the signal sent by the uplink input end through the directional coupler and forwarding the signal to the downlink receiving end when the directional coupler and the downlink receiving end are turned on; and the RF switch is used for receiving the amplified signal of the RF amplifier and sending the signal to the uplink input end through the directional coupler when the directional coupler and the RF amplifier are turned on; The application further comprises a transceiving switching signal end and a digital baseband modulation signal end; the transceiving switching signal end is connected with the RF switch; and the digital baseband modulation signal end is connected with the RF amplifier; wherein, The transceiving switching signal end is used for providing a transceiving switching signal for the RF switch; The RF switch is also used for turning on the directional coupler and the downlink receiving end or the directional coupler and the RF amplifier according to the transceiving switching signal; The digital baseband modulation signal end is used for sending a digital baseband modulation signal to the RF amplifier; The digital baseband modulation signal controls the gain of the RF amplifier.

2. The reflection amplification circuit according to claim 1, characterized by The application further comprises an antenna and a matching network; the antenna is connected with the matching network; and the matching network is also connected with the uplink input end; wherein, The antenna is used for transceiving signals; The matching network is used for impedance matching of the antenna and suppression of interference signals outside a working frequency band.

3. The reflection amplification circuit according to claim 2, characterized by The matching network comprises a first capacitor, a second capacitor and a first inductor; wherein, One end of the first inductor is connected with the antenna; the other end of the first inductor is connected with the uplink input end; one end of the first inductor is also connected with one end of the first capacitor; the other end of the first capacitor is grounded; the other end of the first capacitor is also connected with one end of the second capacitor; and the other end of the second capacitor is grounded.

4. The reflection amplification circuit according to claim 1, characterized by A filter is further installed between the directional coupler and the RF switch; the filter is an acoustic surface wave filter and is used for filtering noises outside a working frequency band.

5. The reflection amplification circuit according to claim 4, characterized by The application further comprises a first resistor; wherein, One end of the first resistor is connected with the isolation end of the directional coupler, the other end of the first resistor is grounded, the through end of the directional coupler is connected with one end of the filter, the other end of the filter is connected with the common end of the radio frequency switch, the control end of the radio frequency switch is connected with the transceiving switching signal end, the normally closed end of the radio frequency switch is connected with the downlink receiving end, the normally open end of the radio frequency switch is connected with the output end of the radio frequency amplifier, the power supply end of the radio frequency amplifier is connected with a power supply, the ground end of the radio frequency amplifier is grounded, the co-directional input end of the radio frequency amplifier is connected with the digital baseband modulation signal end, the reverse input end of the radio frequency amplifier is connected with the coupling end of the directional coupler, and the input end of the directional coupler is connected with the uplink input end.

6. A reflection amplification device, characterized by, The reflection amplification device comprises the reflection amplification circuit according to any one of claims 1-5.

7. The reflection amplifying device according to claim 6, characterized by The reflection amplification device is further connected with a downlink receiving circuit through the downlink receiving end, and the downlink receiving circuit is used for receiving the signal transmitted by the reflection amplification device to the downlink receiving end.

8. A method of reflection amplification for controlling a reflection amplification circuit according to any one of claims 1 to 5, characterized by The reflection amplification method specifically comprises: The directional coupler couples the signal transmitted by the uplink input end to the radio frequency switch to obtain a coupling signal, and transmits the coupling signal to the radio frequency amplifier; The radio frequency amplifier receives the coupling signal, amplifies the coupling signal, and transmits the amplified coupling signal to the radio frequency switch; When the radio frequency switch is turned on between the directional coupler and the downlink receiving end, the radio frequency switch receives the signal transmitted by the uplink input end through the directional coupler, and transmits the signal to the downlink receiving end; when the radio frequency switch is turned on between the directional coupler and the radio frequency amplifier, the radio frequency switch receives the signal amplified by the radio frequency amplifier, and transmits the signal to the uplink input end through the directional coupler.

9. An electronic tag, characterized by The electronic tag comprises the reflection amplification device according to any one of claims 6-7, or the electronic tag applies the reflection amplification method according to claim 8.

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