Substation ultra-high frequency RFID reading and writing device and reading and writing method

Abstract

The application provides a substation ultra-high frequency RFID reading and writing device and a reading and writing method, and belongs to the technical field of RFID. The substation ultra-high frequency RFID reading and writing device comprises a reader, an antenna, a radio frequency cable, a first power divider, a second power divider and an amplifier. One end of the radio frequency cable is connected to the reader, and the other end is connected to the total port of the first power divider. The first power divider and the second power divider are both one-to-two power dividers. The amplifier is connected in series between one branch port of the first power divider and one branch port of the second power divider, and the other branch port of the first power divider and the other branch port of the second power divider are directly connected. The total port of the second power divider is connected to the antenna. The application can compensate for the transmission loss in the radio frequency cable, improve the power of the radio frequency signal and the reading and writing distance of the reader, and flexibly arrange the antenna according to the field conditions and select a smooth signal transmission path.

Description

Technical Field

[0001] This application belongs to the field of RFID technology, specifically relating to an ultra-high frequency RFID reader / writer device and reading / writing method for substations. Background Technology

[0002] RFID (Radio Frequency Identification) is a non-contact automatic identification technology that uses radio frequency signals to automatically identify specific targets and read / write related data without requiring mechanical or optical contact between the identification system and the target. Currently, RFID technology is already being used in substations, such as for collecting status data from electrical equipment.

[0003] Because substations contain a large number of high-voltage electrical devices, the reading device (reader and antenna) must maintain a sufficient safe distance from the electrical equipment when reading data from RFID tags on these devices. Therefore, in existing technologies, readers often use external antennas with high gain to communicate with the tags. The antenna and reader are connected by an RF cable. However, the RF cable attenuates during signal transmission, causing a decrease in the strength of the RF signal emitted by the antenna, which in turn affects the communication distance with the tags. Therefore, the reading distance of existing reading devices is limited and often fails to meet practical needs.

[0004] Therefore, existing technologies consider adding amplifiers to RF cables to improve transmission power. However, most amplifiers are unidirectional, and connecting them in series in the RF line will affect the reader's reception of the return signal. Therefore, the unidirectional isolation problem of the amplifier must be solved when setting up the amplifier.

[0005] For example, patent document CN115276721A proposes an RFID signal reading system based on signal compensation amplification. The system includes an RFID reader and a main antenna system. The main antenna system includes a coupler, at least one power amplifier, and at least two RFID antennas. The number of power amplifiers is less than the number of RFID antennas. Each power amplifier corresponds to one RFID antenna, and RFID antennas with corresponding power amplifier relationships each correspond to one power amplifier. The RFID reader is connected to the coupler. RFID antennas without corresponding power amplifier relationships are directly connected to the coupler. RFID antennas with corresponding power amplifier relationships are connected to the coupler via their respective power amplifiers. In this patent document, the coupler divides the signal generated by the RFID reader into two parts. One part is amplified and transmitted using the first antenna, and the other part is transmitted using the second antenna. When the second antenna receives the return signal from the electronic tag, it can transmit it back to the RFID reader via the coupler and RFID cable, thus overcoming the unidirectional conduction defect of the amplifier. However, this patent document requires at least two antennas, increasing the system application cost. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide a substation ultra-high frequency RFID reading and writing device and reading and writing method to address the shortcomings of the existing technology.

[0007] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0008] A substation UHF RFID reader / writer includes a reader, an antenna, an RF cable, a first power divider, a second power divider, and an amplifier.

[0009] One end of the radio frequency cable is connected to the reader / writer, and the other end is connected to the main port of the first power divider.

[0010] Both the first power divider and the second power divider are 1-to-2 power dividers;

[0011] The amplifier is connected in series between one branch port of the first power divider and one branch port of the second power divider, and the other branch port of the first power divider and the other branch port of the second power divider are directly connected.

[0012] The main port of the second power divider is connected to the antenna.

[0013] Furthermore, the amplifier connected in series between the first power divider and the second power divider comprises at least two cascaded amplifiers.

[0014] Furthermore, the feature is that: both the first power divider and the second power divider are used to divide one radio frequency signal into two radio frequency signals, and both are used to merge two radio frequency signals into one radio frequency signal.

[0015] Furthermore, the reader / writer includes a processing module and an RF module and an interface module electrically connected to the processing module.

[0016] Furthermore, the amplifier has a magnification factor of 1-10.

[0017] Furthermore, the amplifier is characterized by having an amplification effect adjustment knob.

[0018] Furthermore, the feature is that the first power divider, the second power divider, and the amplifier all use SMA interfaces.

[0019] Furthermore, the feature is that the allocation ratio of the two branches of the first power divider and the second power divider is 4:6, and the amplifier is connected in series in the two branches with a ratio of 4.

[0020] Furthermore, the feature is that the signal power is evenly distributed between the two branches of the first power divider and the second power divider.

[0021] A substation UHF RFID reading and writing method, implemented using the aforementioned reading and writing device, includes the following steps:

[0022] The reader generates radio frequency signals;

[0023] The radio frequency signal is assigned as a first radio frequency signal and a second radio frequency signal;

[0024] The first radio frequency signal is amplified.

[0025] The amplified first radio frequency signal is combined with the second radio frequency signal and then transmitted.

[0026] Receive the return signals from RFID electronic tags;

[0027] The return signal is assigned as a first return signal and a second return signal;

[0028] The second return signal is transmitted to the reader / writer.

[0029] RFID technology can be categorized by frequency band into low frequency (LF, 30kHz-300kHz), high frequency (HF, 3MHz-30MHz), ultra-high frequency (UHF, 840MHz-930MHz), and microwave (2.45GHz). UHF RFID transmits signals and energy through magnetic or electric fields, offering longer identification distances; passive electronic tags can achieve a reading distance of approximately 10 meters, and data transmission rates are higher than low or high frequency bands. Furthermore, UHF RFID offers advantages over traditional chip designs, including lower power consumption, higher integration, higher sensitivity, and lower cost. With current packaging technology, UHF RFID has excellent application potential, effectively controlling packaging difficulty and cost, facilitating mass production. The trend towards faster, more accurate, and longer-range reading and writing is towards greater accuracy, and UHF RFID demonstrates significant advantages in these areas. It also facilitates easy networking and system network construction, and boasts strong compatibility. Therefore, UHF RFID represents a crucial trend in future wireless identification technology development and is currently widely used in substations.

[0030] In substations, RFID technology is mainly used to collect status data of high-voltage electrical equipment. RFID tags are often placed directly near or on the electrical equipment. To ensure safety, the RFID reader must maintain a sufficient safe distance from the high-voltage electrical equipment, thus placing higher demands on the RFID read / write distance. Existing technologies primarily improve the reader's read / write distance by increasing its transmission power, improving its sensitivity, using an external antenna, and increasing the antenna gain.

[0031] Meanwhile, substations contain numerous electrical devices or other metal objects. When these devices or objects are present in the communication path with the electronic tags, communication can be interfered with or blocked. Therefore, the reader / writer should be flexibly configured to ensure uninterrupted communication with the electronic tags. In this case, installing an RF cable between the reader / writer and the antenna can increase the application distance and allow for flexible antenna placement, particularly by placing the antenna at a high location. This better eliminates interference from metal objects on the ground and increases the antenna's coverage area.

[0032] However, when using RF cables, the attenuation of the RF signal during transmission within the cable reduces the strength of the RF signal emitted by the antenna, thus affecting the communication distance with the electronic tag. To compensate for this line loss, conventional methods include increasing the reader's signal power, optimizing the RF cable materials, and improving the antenna gain. However, RFID standards limit the maximum power of readers, so their power cannot be increased indefinitely. The line loss of RF cables is generally inversely proportional to the cost of the materials used; using higher-quality materials inevitably increases costs. Antenna gain is also related to size; an excessively large antenna increases costs and is not conducive to installation in substations. Furthermore, RF cable and antenna technologies are already mature, making it difficult to significantly increase RF signal power or improve reading distance by improving these aspects.

[0033] Therefore, existing technologies consider adding amplifiers to the RF cable to improve signal power. However, since amplifiers are unidirectional, series amplifiers in the RF line will affect the reader's reception of the return signal. Therefore, the unidirectional isolation problem of the amplifier must be solved when setting up the amplifier. For example, patent document CN115276721A uses a coupler in series in the RF cable. The coupler splits the signal generated by the RF reader into two parts: one part is amplified and transmitted using the first antenna, and the other part is transmitted using the second antenna. When the second antenna receives the return signal from the electronic tag, it can transmit it back to the RF reader through the coupler and the RF cable. However, this method requires two antennas, increasing system cost.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The reader / writer device provided by this invention includes a reader / writer, a first power divider, an amplifier, a second power divider, and an antenna. Both the first and second power dividers are 1-to-2 power dividers. The reader / writer is connected to the main port of the first power divider via an RF cable. The main port of the second power divider is connected to the antenna. One branch port of the first power divider and one branch port of the second power divider are connected in series with an amplifier. The other branch port of the first power divider and the other branch port of the second power divider are directly connected. When the reader / writer generates an RF signal, the RF signal is transmitted to the first power divider via the RF cable. The first power divider divides the RF signal into two parts. One part is amplified by the amplifier and then transmitted to the second power divider. The other part is directly transmitted to the second power divider. The second power divider combines the two signals and transmits them to the antenna. When the antenna receives the return signal from the electronic tag, the return signal passes through the branch between the second and first power dividers (without an amplifier) ​​and is transmitted to the reader / writer via the RF cable. Because there is a direct connection between the first power divider and the second power divider, the transmission of the return signal to the reader can be ensured, avoiding the blocking of the reverse transmission of the signal when only an amplifier is set.

[0036] Calculations show that the amplifier in this invention significantly increases the power of the received return signal and also significantly increases the read / write distance. Therefore, the longer read / write distance ensures a sufficient safe distance between the read / write device and the pressure-holding electrical equipment. Simultaneously, the RF cable in this invention allows for a wider application range of the antenna, enabling flexible antenna deployment based on site conditions, selection of unobstructed signal transmission paths, and prevention of obstruction between the antenna and the electronic tag by metal objects, thus avoiding interference with the RF signal during spatial transmission. With the RF cable connection, the antenna can also be placed at a higher position, increasing coverage and better eliminating interference from metal objects on the ground.

[0037] This invention utilizes the existing structure of reader / writer devices—where the antenna is directly connected to the reader / writer via an RF cable—by adding a first power divider, an amplifier, and a second power divider near the antenna. This compensates for transmission losses in the RF cable, increases the power of the RF signal, and extends the reader's read / write distance. Furthermore, the first power divider, amplifier, and second power divider all use SMA interfaces, facilitating easy connections between the RF cable and the first power divider, between the second power divider and the antenna, and between the amplifier and the first and second power dividers. The amplifier in this invention also features an amplification adjustment knob, allowing for convenient adjustment of the amplifier's power amplification factor as needed. Therefore, this invention has a simple structure, can directly improve existing products, increases product utilization, and reduces cost waste.

[0038] If the amplification effect of setting only one amplifier is not ideal, the present invention can also connect two or more amplifiers in series between the first power divider and the second power divider. These amplifiers are cascaded in sequence, and the cascaded amplifier will have a greater amplification effect, thereby giving the present invention a greater power enhancement effect.

[0039] The preferred branch allocation ratio of the first and second power dividers in this invention is 4:6, and the next most preferred ratio is 5:5. Using a branch allocation ratio of 4:6 or 5:5 enables this read / write device to obtain better signal enhancement. Attached Figure Description

[0040] The present application will now be described in further detail with reference to the accompanying drawings.

[0041] Figure 1 One of the schematic diagrams of Embodiment 1 of this application;

[0042] Figure 2 : A schematic diagram of the reader / writer in Embodiment 1 of this application;

[0043] Figure 3 : A second schematic diagram of Embodiment 1 of this application;

[0044] Figure 4 : Flowchart of Embodiment 2 of this application;

[0045] Wherein: 101-reader, 102-antenna, 103-RF cable, 104-first power divider, 105-second power divider, 106-amplifier, 201-processing module, 202-RF module, 203-interface module. Detailed Implementation

[0046] To better understand this application, the content of this application is further explained clearly below with reference to embodiments and accompanying drawings. However, the protection scope of this application is not limited to the embodiments described below. Numerous specific details are set forth in the following description to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without one or more of these details.

[0047] Example 1:

[0048] The purpose of this embodiment is to provide a substation UHF RFID reader / writer device, such as... Figure 1 As shown, the read / write device includes a reader 101, an antenna 102, a first power divider 104, a second power divider 105, and an amplifier 106.

[0049] The reader 101 is used to read and write RFID electronic tags. Specifically, the reader 101 is used for data demodulation, data processing, information interaction, and data transmission.

[0050] like Figure 2 As shown, the reader 101 includes a processing module 201, a radio frequency (RF) module 202, and an interface module 203 electrically connected to the processing module 201. The RF module 202 modulates the data to be sent by the reader 101 to the RFID tag and ultimately transmits the data to free space via the antenna 102. After receiving the information, the RFID tag demodulates, processes, and modulates the RF signal before transmitting it back to the antenna 102. The antenna 102 then returns the received signal to the RF module 202 for demodulation, extracting the data returned by the RFID tag. The processing module 201 performs internal data conversion within the reader 101, such as encoding / decoding transmitted / received signals, and converting and processing protocol packets. The processing module 201 also performs power modulation, controls the RF module 202 to transmit and receive signals, performs signal modulation and demodulation commands, and executes commands transmitted by external devices via the interface module 203. The interface module 203 is used to connect the reader 101 to an external device and to perform data and command interactions with the external device; the external device acts as a data processing system, such as a common computer device.

[0051] Antenna 102 is used for communication between reader 101 and RFID electronic tag. Specifically, antenna 102 is used to transmit the information modulated by reader 101 into free space in the form of radio frequency microwaves, and can also receive the signal transmitted back to reader 101 after the RFID electronic tag responds.

[0052] In the prior art, the reader 101 is directly connected to the antenna 102, which can be built into the reader 101 or externally mounted. However, in the application environment of substations, in order to ensure a sufficient safe distance from electrical equipment, the RFID reader must have a sufficient reading and writing distance.

[0053] To improve signal strength, this invention employs an external antenna 102, which is connected to the reader 101 via an RF cable 103. This allows for flexible antenna placement and a longer application distance; it can also be positioned at higher locations, providing a wider signal coverage area. However, the RF cable 103 has line loss, causing signal attenuation during RF signal transmission. Therefore, this invention also includes a first power divider 104, a second power divider 105, and an amplifier 106 at the front end of the antenna 102 to compensate for the line loss of the RF cable 103 and simultaneously improve the strength of the RF signal transmitted by the antenna 102.

[0054] Both the first power divider 104 and the second power divider 105 are 1-to-2 power dividers, capable of splitting one RF signal into two RF signals, and also capable of reversing the process to merge two RF signals into one RF signal. The main port of the first power divider 104 is represented by C1, and its two branch ports are represented by A1 and B1, respectively. The main port of the second power divider 105 is represented by C2, and its two branch ports are represented by A2 and B2, respectively.

[0055] The main port C1 of the first power divider 104 is connected to the reader 101 via RF cable 103. The main port C2 of the second power divider 105 is connected to the antenna 102 via RF jumper. The port B1 of the first power divider 104 is connected to the port B2 of the second power divider 105 via RF jumper. An amplifier 106 is also connected in series between the port A1 of the first power divider 104 and the port A2 of the second power divider 105 via RF jumper.

[0056] Amplifier 106 is used to amplify the radio frequency signal output from port A1 and transmit it to port A2. Amplifier 106 can only transmit in one direction.

[0057] In one possible implementation, the amplifier 106 has a magnification of 1-10x. The amplifier 106 uses an SMA interface and also has a magnification adjustment knob. Simultaneously, both the first power divider 104 and the second power divider 105 use SMA interfaces, facilitating direct connection between the antenna 102, amplifier 106, first power divider 104, and second power divider 105.

[0058] In another possible implementation, such as Figure 3 As shown, at least two amplifiers 106 are connected in series between port A1 of the first power divider 104 and port A2 of the second power divider 105. These amplifiers 106 are cascaded in sequence, and the cascaded amplifiers 106 will have a greater amplification effect.

[0059] In this embodiment, during operation, the reader 101 generates a radio frequency (RF) signal, which is transmitted via RF cable 103 to the first power divider 104. The first power divider 104 splits the RF signal into two signals. One signal is output from port A1, amplified by amplifier 106, and then input from port A2 of the second power divider 105. The other signal is transmitted from port B1 to port B2 of the second power divider 105. The second power divider 105 combines the two signals and sends them from port C2 to antenna 102. Antenna 102 transmits and receives RF signals externally. When antenna 102 receives the radio frequency signal returned by the RFID electronic tag, it transmits the returned signal to port C2 of the second power divider 105. The second power divider 105 divides the returned signal into two signals. One signal is discarded (amplifier 106 conducts unidirectionally), and the other signal is transmitted from port B2 to port B1 of the first power divider 104. The first power divider 104 transmits the signal input from port B1 to reader 101 via radio frequency cable 103, and the reader 101 processes the signal.

[0060] In the following, X represents the loss of the radio frequency signal transmitted in the radio frequency cable 103, Y represents the space loss after the radio frequency signal is transmitted to the electronic tag and transmitted back, P0 represents the power of the reader 101, the distribution ratio of the two branches of the first power divider 104 and the second power divider 105 is 4:6, and the amplification factor of the amplifier 106 is 10.

[0061] When the antenna 102 is directly connected to the reader 101 via the radio frequency cable 103, the power of the return signal received by the reader 101 is P1 = P0 - XYX.

[0062] When the read / write device uses, such as Figure 1 When the antenna 102 is configured, the power P of the radio frequency signal transmitted is... TX = (P0-X)×0.4×10+(P0-X)×0.6=(P0-X)×4.6, where p is the power of the RFID tag's return signal received by antenna 102. RX =p TX -Y, the power of the feedback signal received by reader 101, P2 = P RX ×0.6-X=(P TX -Y)×0.6-X=((P0-X)×4.6-Y)×0.6-X=(P0-X)×2.76-0.6YX.

[0063] Comparing the two scenarios, when the first power divider 104, the second power divider 105, and the amplifier 106 are not configured, P1 = (P0 - X) × 1 - YX. When the first power divider 104, the second power divider 105, and the amplifier 106 are configured, P2 = (P0 - X) × 2.76 - 0.6YX. From P2 - P1 = (P0 - X) × 1.76 + 0.4Y, it can be seen that using... Figure 1 When the structure is modified, the power of the return signal received by the reader 101 is significantly enhanced, thus increasing the read / write distance.

[0064] To reduce complexity during application, the first power divider 104 and the second power divider 105 use the same specifications, with identical distribution ratios for their two branches. Using the above calculation method, with the amplifier 106 having a gain of 10, the relationship between the enhanced power and the branch distribution ratios of the first power divider 104 and the second power divider 105 is as follows:

[0065] Power divider branch distribution ratio <![CDATA[Enhanced power (P2 - P1)]]> 1:9 <![CDATA[(P0-X)×0.71+0.1Y]]> 2:8 <![CDATA[(P0-X)×1.24+0.2Y]]> 3:7 <![CDATA[(P0-X)×1.59+0.3Y]]> 4:6 <![CDATA[(P0-X)×1.76+0.4Y]]> 5:5 <![CDATA[(P0-X)×1.75+0.5Y]]> 6:4 <![CDATA[(P0-X)×1.56+0.6Y]]> 7:3 <![CDATA[(P0-X)×1.19+0.7Y]]> 8:2 <![CDATA[(P0-X)×0.64+0.8Y]]> 9:1 <![CDATA[-(P0-X)×0.09+0.9Y]]>

[0066] As shown in the table above, when the branch allocation ratio of the first power divider 104 and the second power divider 105 is 4:6 or 5:5, the device can achieve better signal gain. Therefore, in one possible implementation, the allocation ratio of the two branches of the first power divider 104 and the second power divider 105 is 4:6 or 5:5. When the RF signal spatial loss Y is relatively small, the preferred branch allocation ratio is 4:6.

[0067] Example 2:

[0068] The purpose of this embodiment is to provide a method for reading and writing ultra-high frequency RFID in substations, implemented using the reading and writing device described in Embodiment 1, such as... Figure 4 As shown, the read / write method includes:

[0069] S1, Reader 101 generates radio frequency signals.

[0070] Reader 101 generates radio frequency signals that need to be sent to the RFID electronic tag.

[0071] S2. Distribute the radio frequency signal into a first radio frequency signal and a second radio frequency signal.

[0072] The radio frequency signal generated by the reader 101 is transmitted to the first power divider 104 via the radio frequency cable 103. It is input through the C1 port of the first power divider 104 and then divided into two signals, a first radio frequency signal and a second radio frequency signal, by the first power divider 104. The first radio frequency signal is output through the A1 port of the first power divider 104, and the second radio frequency signal is output through the B1 port of the first power divider 104.

[0073] S3. Amplify the first radio frequency signal.

[0074] The first radio frequency signal output from the A1 port of the first power divider 104 is transmitted to the amplifier 106. After being amplified by the amplifier 106, it is transmitted to the second power divider 105.

[0075] S4. The amplified first radio frequency signal and the second radio frequency signal are combined and then transmitted.

[0076] The second radio frequency signal and the amplified first radio frequency signal are transmitted to the second power divider 105. The second radio frequency signal is input through port B2 of the second power divider 105, and the amplified first radio frequency signal is input through port A2 of the second power divider 105. The second power divider 105 combines the two input signals into a new radio frequency signal and outputs it through port C2 to the antenna 102, which then transmits it to the outside.

[0077] S5. Receive the return signal from the RFID electronic tag.

[0078] When the RFID electronic tag receives the radio frequency signal transmitted by the antenna 102, it demodulates, processes, and modulates the radio frequency signal, and then transmits back a signal carrying data information. The antenna 102 can receive the signal transmitted back by the RFID electronic tag.

[0079] S6. Assign the return signal to the first return signal and the second return signal.

[0080] After receiving the feedback signal from the RFID electronic tag, the antenna 102 transmits the signal to the second power divider 105. The second power divider 105 divides the feedback signal into a first feedback signal and a second feedback signal. The first feedback signal is output from port A2 and then discarded. The second feedback signal is output from port B2 to port B1 of the first power divider 104, and then output from port C1 of the first power divider 104.

[0081] S7. The second return signal is transmitted to the reader 101.

[0082] The second feedback signal output from the C1 port of the first power divider 104 is transmitted to the reader 101 via the radio frequency cable 103, and the reader 101 demodulates and processes the feedback signal.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of this application, as long as they do not depart from the spirit and scope of the technical solutions of this application, should be covered within the scope of the claims of this application.

Claims

1. A substation UHF RFID reader / writer device, characterized in that: Includes a reader / writer, antenna, RF cable, first power divider, second power divider, and amplifier; One end of the radio frequency cable is connected to the reader / writer, and the other end is connected to the main port of the first power divider. Both the first power divider and the second power divider are 1-to-2 power dividers; The amplifier is connected in series between one branch port of the first power divider and one branch port of the second power divider, and the other branch port of the first power divider and the other branch port of the second power divider are directly connected. The main port of the second power divider is directly connected to the antenna; Both the first power divider and the second power divider are used to divide one radio frequency signal into two radio frequency signals, and both are used to reverse the process to combine the two radio frequency signals into one radio frequency signal; The first power divider and the second power divider each have a 4:6 ratio for their two branches, and the amplifier is connected in series in the two branches with a ratio of 4.

2. The substation UHF RFID reader / writer device according to claim 1, characterized in that: The amplifier connected in series between the first power divider and the second power divider includes at least two cascaded amplifiers.

3. The substation UHF RFID reader / writer device according to claim 1, characterized in that: The reader / writer includes a processing module, a radio frequency module, and an interface module electrically connected to the processing module.

4. The substation UHF RFID reader / writer device according to claim 1, characterized in that: The amplifier has a magnification factor of 1-10.

5. The substation UHF RFID reader / writer device according to claim 1, characterized in that: The amplifier is equipped with a knob for adjusting the amplification effect.

6. The substation UHF RFID reader / writer device according to claim 1, characterized in that: The first power divider, the second power divider, and the amplifier all use SMA interfaces.

7. A method for reading and writing ultra-high frequency RFID in a substation, characterized in that: Implemented using the read / write device according to any one of claims 1-6, the read / write method includes: The reader generates radio frequency signals; The radio frequency signal is assigned as a first radio frequency signal and a second radio frequency signal; The first radio frequency signal is amplified. The amplified first radio frequency signal is combined with the second radio frequency signal and then transmitted. Receive the return signals from RFID electronic tags; The return signal is assigned as a first return signal and a second return signal; The second return signal is transmitted in reverse along the transmission path of the second radio frequency signal to the reader / writer.

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