Method and system for providing power supply for RFID tag in wireless power supply mode

Abstract

The invention belongs to the technical field of radio frequency identification, and particularly relates to a method and a system for providing a power supply for an RFID tag in a wireless power supply mode. According to the method, extra energy is provided for the RFID electronic tag in a wireless mode, and the transmitting power and the receiving sensitivity of the RFID electronic tag can be effectively improved under the conditions that the tag size is not obviously increased and a battery is not added, so that the working distance of the tag is increased, and the anti-interference capability of the tag is improved; according to the method, a dynamic adjustment method for the emission power of the excitation source is designed, the emission power of the excitation source can be dynamically adjusted according to label signal intensity information, phase information and other information read by a reader, the emission power of the label is always kept in the optimal state meeting the reading requirement, and energy waste is avoided.

Description

Technical Field

[0001] The present invention belongs to the field of wireless radio frequency identification technology, and in particular relates to a method and system for providing power to an RFID tag by wireless power supply. Background Art

[0002] Currently, ultra-high frequency (UHF) RFID tags are widely used in logistics, warehousing, and other fields, replacing traditional barcode and QR code tags. RFID tags can be read in batches over long distances, an advantage over traditional barcode tags, effectively improving scanning efficiency.

[0003] However, RFID tags are passive tags. Their operating energy comes from the energy radiated by the RFID reader. At long distances or when the tag is obscured, the energy received and radiated by the tag will be significantly attenuated, causing the reader to be unable to read the tag information, resulting in missed reads. To reduce the probability of missed reads, methods are often used to increase the RFID reader's transmit power, increase the antenna gain, or use other methods to improve the performance of the tag. However, increasing the antenna gain will result in a larger antenna size, which in turn increases the cost. Furthermore, if the tag performance is to be significantly improved, the tag size will also increase, making it unsuitable for use with smaller items. Larger tags also increase the cost.

[0004] Although the use of active tags can increase the tag's transmission power, the battery needs to be replaced regularly, which increases the workload, causes the tag to become larger in size and increase the cost, which is not conducive to its application in fields such as logistics and cargo in and out warehousing management. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a method and system for providing power to RFID tags through wireless power supply, thereby providing additional energy to RFID electronic tags in a wireless manner, thereby improving the transmission power and receiving sensitivity of RFID electronic tags without significantly increasing the tag size or adding batteries, thereby improving the tag's working distance and anti-interference ability.

[0006] In order to solve the above problems, the technical solutions adopted by the present invention are as follows: A method for providing power to an RFID tag by wireless power supply comprises the following steps: (1) After receiving the tag reading instruction, the host computer controls the excitation source to send electromagnetic waves, and the RFID reader reads the tag information at the same time; (2) The RFID reader sends the tag information it reads to the host computer, which analyzes the tag information and calculates the optimal excitation source transmission power. Based on the calculated optimal excitation source transmission power, the host computer sends instructions to the excitation source to adjust the transmission power of the excitation source. (3) The host computer determines whether the reading is completed. If not, the host computer returns to step (1). If the reading is completed, the host computer sends a command to the excitation source, and the excitation source stops sending electromagnetic waves. In step (2), the process of calculating and adjusting the transmit power is as follows: (2.1) Under normal operating conditions, collect RSSI data and phase values ​​of the RFID tag reflected signal at different transmission powers of the excitation source to form a data set including tag ID, excitation source transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase; (2.2) Calculate the distance between the tag and the RFID antenna using the RFID signal frequency and signal phase; The calculation process is to use different frequencies to read the tag information each time, which are and , and the corresponding wavelengths are and , the phase of the received tag reflected signal is and ,in 、 , the relationship between phase and distance is: ; ; Calculate the distance ,in, is the speed of light, ; The phase difference introduced by the reader transmitting circuit, The phase difference introduced by the reader receiving circuit, The phase difference introduced for the RFID tag characteristics, is a positive integer; The calculated distance value is used to filter the data received from the same tag, and the data closest to the antenna, that is, the data with the smallest distance value, is selected; (2.3) Determine the minimum RSSI value based on the tag performance and field test results ( ), if the signal strength is less than this value, the tag miss reading rate is >90%; (2.4) Construct a neural network to extract the features of the data set filtered in step (2.2) and learn the relationship between the excitation source transmission power and the tag reflected signal strength RSSI: (2.4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain the loss value compared to the actual excitation source transmission power; ; in, is the excitation source transmission power predicted by RSSI, is the current transmitting power of the excitation source; The Adam optimizer is used to optimize the network parameters so that Minimum, get Mapping relationship between RSSI ; (2.4.2) Based on the prediction results of the neural network, use the genetic algorithm to search for the global optimal solution under the constraints. Value, predicted using a neural network The value is used as the gene to predict the RSSI value, and the constraint conditions are integrated into the fitness calculation through the penalty function, where the fitness , is the penalty coefficient, which is determined by the deviation between the predicted RSSI value and the actual RSSI. The greater the deviation, the greater the penalty coefficient. The transmission power is obtained through the genetic algorithm. The global optimal solution _opt; (2.5) The host computer software sends a command to the excitation source to set its power to _opt.get The RSSI values ​​of all tag reflection signals read at _opt power are calculated, and the average RSSI value is obtained, that is, the average optimal , when reading later, fine-tune the excitation source transmission power on this basis, so that the overall RSSI value obtained each time is consistent with the RSSI optimal value The average deviation value is less than the threshold ,Right now , The value of is determined according to the actual scenario; According to the formula - ; in, is the number of labels, For the Tags value; like , , the power remains unchanged; like , , The power decreases, The power increases; like , , The power decreases, The power increases; in, is the adjusted power value, is the power value before adjustment, 、 The power adjustment threshold is determined based on actual tests.

[0007] Furthermore, in step (2.1), a tag can be read repeatedly multiple times, thereby obtaining multiple pieces of data corresponding to the tag.

[0008] Furthermore, in step (2.4.2), the constraint condition is , ,in The maximum transmission power of the excitation source is determined by the hardware design of the excitation source. When working, the transmission power of the excitation source is less than the maximum transmission power. The minimum value allowed by RSSI. If the value is less than this, the tag may not be read. On-site measurement based on the on-site environment, RFID reader transmission power and tag performance.

[0009] Furthermore, the adjustment step of the transmission power of the excitation source is as low as 1 dBm and as high as 3 dBm.

[0010] A method for adjusting the emission power of an excitation source comprises the following steps: (1) Under normal working conditions, the RSSI data and phase values ​​of the RFID tag reflected signal at different transmission powers of the excitation source are collected to form a data set including tag ID, transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase; (2) Calculate the distance between the tag and the RFID antenna through the RFID signal frequency and signal phase; The calculation process is to use different frequencies to read the tag information each time, which are and , and the corresponding wavelengths are and , the phase of the received tag reflected signal is and ,in 、 , the relationship between phase and distance is: ; ; Calculate the distance ,in, is the speed of light, ; The phase difference introduced by the reader transmitting circuit, The phase difference introduced by the reader receiving circuit, The phase difference introduced for the RFID tag characteristics, is a positive integer; The calculated distance value is used to filter the data received from the same tag, and the data closest to the antenna, that is, the data with the smallest distance value, is selected; (3) Determine the minimum RSSI value based on the tag performance and field test results ( ), the signal strength is less than this value, and the tag missed reading rate is >90%; (4) Construct a neural network to extract the features of the data set filtered in step (2.2) and learn the relationship between the excitation source transmission power and the tag reflected signal strength RSSI: (4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain the loss value compared with the actual excitation source transmission power; ; in, is the excitation source transmission power predicted by RSSI, is the current transmitting power of the excitation source; The Adam optimizer is used to optimize the network parameters so that Minimum, get Mapping relationship between RSSI ; (4.2) Based on the prediction results of the neural network, use the genetic algorithm to search for the global optimal solution under the constraints. Value, predicted using a neural network The value is used as the gene to predict the RSSI value, and the constraint conditions are integrated into the fitness calculation through the penalty function, where the fitness , is the penalty coefficient, which is determined by the deviation between the predicted RSSI value and the actual RSSI. The greater the deviation, the greater the penalty coefficient. The transmission power is obtained through the genetic algorithm. The global optimal solution _opt; (5) The host computer software sends a command to the excitation source to set its power to _opt.get The RSSI values ​​of all tag reflection signals read at _opt power are calculated, and the average RSSI value is obtained, that is, the average optimal , when reading later, fine-tune the excitation source transmission power on this basis, so that the overall RSSI value obtained each time is consistent with the RSSI optimal value The average deviation value is less than the threshold ,Right now , The value of is determined according to the actual scenario; According to the formula - ; in, is the number of labels, For the Tags value; like , , the power remains unchanged; like , , The power decreases, The power increases; like , , The power decreases, The power increases; in, is the adjusted power value, is the power value before adjustment, 、 is the power adjustment threshold, which is determined based on actual tests. After adjustment, the host computer software will set the excitation source power to .

[0011] A system applied according to the above method, the system includes an electronic tag module, an RFID reader module, an excitation source module and a host computer module; The electronic tag module includes an RFID antenna and an energy harvesting antenna; The RFID reader module includes a reader antenna, the excitation source module includes an excitation source antenna, and the host computer is communicatively connected to the RFID reader module and the excitation source module at the same time; The reader sends a read instruction to the RFID tag through the reader antenna to read the RFID tag information; The excitation source antenna uses an ISM frequency band 5.8 GHz signal to transmit a 5.8 GHz continuous electromagnetic wave signal to the electronic tag module.

[0012] Compared with the prior art, the present invention has the following beneficial effects: This method provides additional energy to RFID electronic tags in a wireless manner, which can effectively improve the transmission power and receiving sensitivity of RFID electronic tags without significantly increasing the tag size or adding batteries, thereby improving the tag's working distance and anti-interference ability.

[0013] This method also designs a dynamic adjustment method for the excitation source transmission power, which can dynamically adjust the excitation source transmission power according to the tag signal strength information and phase information read by the reader, so that the tag transmission power is always maintained in the optimal state to meet the reading needs, avoiding energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of a flow chart of the steps of the method described in the present invention; Figure 2 Schematic diagram of the module structure of the system of the present invention; DETAILED DESCRIPTION The present invention will be further described below with reference to specific embodiments.

[0015] like Figure 1 As shown, the method of providing power to an RFID tag by wireless power supply according to the present invention includes the following steps: (1) After the host computer receives the tag reading instruction from the client server, it controls the excitation source to send electromagnetic wave signals to provide energy to the electronic tag, and at the same time controls the RFID reader to start reading the RFID tag information; (2) The RFID reader sends the tag information it reads to the host computer. The software in the host computer analyzes the tag information, calculates the optimal excitation source transmission power, and sends instructions to the excitation source to adjust the excitation source's transmission power. In this embodiment, the excitation source transmits a 5.8 GHz RF signal to power the electronic tag. To conserve energy and extend the lifespan of the device, the transmission power must be minimized while ensuring that the tag can be correctly read. The RFID reader can obtain the electronic tag's signal strength (RSSI value) and phase information. A lower RSSI value indicates a lower strength of the tag's reflected signal. By analyzing the RSSI value, it can be determined whether the current transmission power is too high or too low. A low RSSI value indicates a risk of tag unreadability and requires increasing the excitation source's transmission power. When all tags can be read, excessively high excitation source transmission power can waste energy or cause surrounding tags to be read, resulting in interference. In actual use, factors such as the electronic tag's attachment direction, position, distance from the RFID reader, differences in the tag's performance, and multipath effects can affect the RSSI value, leading to inaccurate feedback information. Therefore, phase information is introduced to reflect changes in the tag's position or the tag's signal reflection path. Ideally, if the tag's position or the reflected signal path remains unchanged, the phase information will also remain unchanged. By combining these parameters, we can evaluate whether the current excitation source's transmit power is optimal. The purpose of power adjustment is to achieve an ideal RSSI value at a lower excitation source transmit power, thereby ensuring that tags are fully read and achieving the lowest missed read rate.

[0016] Therefore, the process of calculating and adjusting the transmit power described in the present invention is: (2.1) Under normal working conditions, collect the RSSI data and phase values ​​of the RFID tag reflected signal at different transmission powers of the excitation source to form a data set {[TagID_1, TxPower_1, RSSI_1, RFID_Tx_Power_1, RFID_Freq_1, RFID_Phase_1]}...{[TagID_N, TxPower_N, RSSI_N, RFID_Tx_Power_N, RFID_Freq_N, RFID_Phase_N]} containing the tag ID (TagID), transmission power (TxPower), signal strength (RSSI), RFID reader transmission power (RFIS_Tx_Power), RFID signal frequency (RFID_Freq), and signal phase (RFID_Phase); During the reading process, a tag can be read repeatedly multiple times to obtain multiple pieces of data corresponding to the tag.

[0017] (2.2) Due to reflections from the tag's surroundings, the tag's path may change, or the tag may be in motion, causing the phase of the reflected signal to change. This can cause the RSSI of multiple pieces of data from the same tag to change. Therefore, the distance between the tag and the RFID antenna can be calculated based on the RFID signal frequency and signal phase. The calculation process is to use different frequencies to read the tag information each time, which are and , and the corresponding wavelengths are and , the phase of the received tag reflected signal is and ,in 、 , the relationship between phase and distance is: ; ; Calculate the distance ,in, is the speed of light, ; The phase difference introduced by the reader transmitting circuit, The phase difference introduced by the reader receiving circuit, The phase difference introduced for the RFID tag characteristics, is a positive integer; The calculated distance value is used to filter the data received from the same tag, and the data closest to the antenna, that is, the data with the smallest distance value, is selected, thereby reducing the data volume; (2.3) Determine the minimum RSSI value based on the tag performance and field test results ( min), the signal strength is less than this value, and the tag missed reading rate is greater than 90%; (2.4) Construct a neural network to extract the features of the data set filtered in step (2.2) and learn the relationship between the excitation source transmission power and the tag reflected signal strength RSSI: (2.4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain the loss value compared to the actual excitation source transmission power; ; in, is the excitation source transmission power predicted by RSSI, is the current transmitting power of the excitation source; The Adam optimizer is used to optimize the network parameters so that Minimum, get Mapping relationship between RSSI ; (2.4.2) Based on the prediction results of the neural network, use the genetic algorithm to search for the global optimal solution under the constraints. Value, predicted using a neural network The value is used as the gene to predict the RSSI value, and the constraint conditions are integrated into the fitness calculation through the penalty function, where the fitness , is the penalty coefficient, which is determined by the deviation between the predicted RSSI value and the actual RSSI. The greater the deviation, the greater the penalty coefficient. The transmission power is obtained through the genetic algorithm. The global optimal solution _opt; The constraints are , ,in The maximum transmission power of the excitation source is determined by the hardware design of the excitation source. When working, the transmission power of the excitation source is less than the maximum transmission power. The minimum value allowed by RSSI. If the value is less than this, the tag may not be read. On-site measurement based on the on-site environment, RFID reader transmission power and tag performance.

[0018] (2.5) The host computer software sends a command to the excitation source to set its power to _opt.get The RSSI values ​​of all tag reflection signals read at _opt power are calculated, and the average RSSI value is obtained, that is, the average optimal , when reading subsequently, fine-tune the excitation source transmission power on this basis, so that the overall RSSI value obtained each time is distributed near the optimal value, so that the overall RSSI value is close to the RSSI optimal value The average deviation value is less than the threshold ,Right now , The value of is determined according to the actual scenario; The adjustment step of the transmission power of the excitation source is as follows: the minimum is 1dBm and the maximum is 3dBm; According to the formula - ; in, is the number of labels, For the Tags value; like , , the power remains unchanged; like , , The power decreases, The power increases; like , , The power decreases, The power increases; in, is the adjusted power value, is the power value before adjustment, 、 is the power adjustment threshold, which is determined based on actual tests. After adjustment, the host computer software will set the excitation source power to .

[0019] By optimizing the excitation source power Based on the _opt, further fine-tuning of the excitation source's transmit power allows for faster tag reading. By testing and learning from RFID tags attached to multiple batches of goods, the optimal excitation source transmit power is determined. This optimal transmit power is then used to power the tags for normal reading. If there are significant changes in tag performance or in the field environment, the system will readjust the excitation source's transmit power. The excitation source and RFID reader are designed as separate components, operating synchronously without interfering with each other, improving reading efficiency.

[0020] In this technical solution, RFID tags are designed to harvest electromagnetic energy from the space environment, drawing power from both space and the RFID reader, ensuring a stable energy supply. A dedicated excitation source, coupled with wireless radio frequency radiation, radiates electromagnetic signals to the RFID tag. This solution utilizes a 5.8 GHz signal in the ISM band, continuously radiating 5.8 GHz electromagnetic signals to the RFID tag, providing the necessary energy for operation. Since UHF RFID operates in the 840-960 MHz band and the excitation source operates at 5.8 GHz, this signal is not affected.

[0021] In this solution, the control software is run by the host computer to coordinate the RFID reader and the excitation source. According to the data information such as the tag signal strength and phase read by the reader, the excitation source transmission power is dynamically adjusted, so that the tag transmission power is always maintained at the optimal state to meet the reading needs, avoiding energy waste.

[0022] like Figure 2 As shown, based on the above method, the system used by the method of the present invention includes an electronic tag module, an RFID reader module, an excitation source module and a host computer module; The electronic tag module includes an RFID antenna and an energy harvesting antenna; The RFID reader module includes a reader antenna, the excitation source module includes an excitation source antenna, and the host computer is communicatively connected with the RFID reader module and the excitation source module at the same time; The reader antenna sends RFID instructions to the RFID antenna to read the RFID tag information; The excitation source antenna uses the 5.8 GHz signal in the ISM frequency band to transmit a 5.8 GHz continuous electromagnetic wave signal to the electronic tag module.

Claims

1. A method for providing power to an RFID tag by wireless power supply, characterized in that: The following steps are involved: (1) After receiving the tag reading instruction, the host computer controls the excitation source to send electromagnetic waves, and the RFID reader reads the tag information at the same time; (2) The RFID reader sends the tag information it reads to the host computer, which analyzes the tag information and calculates the optimal excitation source transmission power. Based on the calculated optimal excitation source transmission power, the host computer sends instructions to the excitation source to adjust the transmission power of the excitation source. (3) The host computer determines whether the reading is completed. If not, the host computer returns to step (1). If the reading is completed, the host computer sends a command to the excitation source, and the excitation source stops sending electromagnetic waves. In step (2), the process of calculating and adjusting the transmit power is as follows: (2.1) Under normal operating conditions, collect RSSI data and phase values ​​of the RFID tag reflected signal at different transmission powers of the excitation source to form a data set including tag ID, transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase; (2.2) Calculate the distance between the tag and the RFID antenna using the RFID signal frequency and the phase value of the tag’s reflected signal; The calculation process is that the RFID reader uses different frequencies to read the tag information each time, which are and , and the corresponding wavelengths are and , the phase of the received tag reflected signal is and ,in 、 , the relationship between phase and distance is: ； ； Calculate the distance ,in, is the speed of light, ; The phase difference introduced by the reader transmitting circuit, The phase difference introduced by the reader receiving circuit, The phase difference introduced for the RFID tag characteristics, is a positive integer; Using the calculated distance value, filter the data received from the same tag in step (2.1) and select the data closest to the antenna, i.e., the data with the smallest distance value; (2.3) Determine the minimum RSSI value based on the tag performance and field test results ( ), if the signal strength is less than this value, the tag missed reading rate is greater than 90%; (2.4) Construct a neural network to extract the features of the data set filtered in step (2.2) and learn the relationship between the excitation source transmission power and the tag reflection signal RSSI: (2.4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain the loss value between the predicted excitation source transmission power and the actual excitation source transmission power; ； in, is the excitation source transmission power predicted by RSSI, is the current transmitting power of the excitation source; The Adam optimizer is used to optimize the network parameters so that Minimum, get Mapping relationship between RSSI ; (2.4.2) Based on the prediction results of the neural network, use the genetic algorithm to search for the global optimal solution under the constraints. Value, predicted using a neural network The value is used as the gene to predict the RSSI value, and the constraint conditions are integrated into the fitness calculation through the penalty function, where the fitness , is the penalty coefficient, which is determined by the deviation between the predicted RSSI value and the actual RSSI. The greater the deviation, the greater the penalty coefficient. The transmission power is obtained through the genetic algorithm. The global optimal solution _opt; (2.5) The host computer software sends a command to the excitation source, setting its power to the value obtained in step (2.4.2). _opt, get The RSSI values ​​of all tag reflection signals read at _opt power are calculated, and the average RSSI value is obtained, that is, the average optimal , when reading later, fine-tune the excitation source transmission power based on this, so that the overall RSSI value distribution is at the optimal value Nearby, that is, the overall RSSI value and the RSSI optimal value The average deviation value is less than the threshold ,Right now , The value of is determined according to the actual scenario; According to the formula - ； in, is the number of labels, For the Tags value; like , , the power remains unchanged; like , , The power decreases, The power increases; like , , The power decreases, The power increases; in, is the adjusted power value, is the power value before adjustment, 、 The power adjustment threshold is determined according to actual test. After adjustment, the host computer software will set the excitation source power to .

2. The method for providing power to an RFID tag by wireless power supply according to claim 1, wherein: In step (2.1), a tag can be read repeatedly multiple times to obtain multiple pieces of data corresponding to the tag.

3. The method for providing power to an RFID tag by wireless power supply according to claim 1, wherein: In step (2.4.2), the constraints are , ,in The maximum transmission power of the excitation source is determined by the hardware design of the excitation source. The transmission power of the excitation source is less than the maximum transmission power during operation. The minimum value allowed for RSSI.

4. The method for providing power to an RFID tag by wireless power supply according to claim 1, wherein: The minimum adjustment step of the emission power of the excitation source is 1 dBm, and the maximum is 3 dBm.

5. A method for adjusting the emission power of an excitation source, characterized in that: The following steps are involved: (1) Under normal working conditions, the RSSI data and phase values ​​of the RFID tag reflected signal at different transmission powers of the excitation source are collected to form a data set including the tag ID, excitation source transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase; (2) Calculate the distance between the tag and the RFID antenna through the RFID signal frequency and signal phase; The calculation process is that, each time the tag is read, two different frequencies are used to read the tag information, namely and , and the corresponding wavelengths are and , the phase of the received tag reflected signal is and ,in 、 , the relationship between phase and distance is: ； ； Calculate the distance ,in, is the speed of light, ; The phase difference introduced by the reader transmitting circuit, The phase difference introduced by the reader receiving circuit, The phase difference introduced for the RFID tag characteristics, is a positive integer; The calculated distance value is used to filter the data received from the same tag, and the data closest to the antenna, that is, the data with the smallest distance value, is selected; (3) Determine the minimum RSSI value based on the tag performance and field test results ( ), if the signal strength is less than this value, the tag miss reading rate is >90%; (4) Construct a neural network to extract the features of the data set filtered in step (2.2) and learn the relationship between the excitation source transmission power and the tag reflected signal strength RSSI: (4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain the loss value compared with the actual excitation source transmission power; ； in, is the excitation source transmission power predicted by RSSI, is the current transmitting power of the excitation source; The Adam optimizer is used to optimize the network parameters so that Minimum, get Mapping relationship between RSSI ; (4.2) Based on the prediction results of the neural network, use the genetic algorithm to search for the global optimal solution under the constraints. Value, predicted using a neural network The value is used as the gene to predict the RSSI value, and the constraint conditions are integrated into the fitness calculation through the penalty function, where the fitness , is the penalty coefficient, which is determined by the deviation between the predicted RSSI value and the actual RSSI. The greater the deviation, the greater the penalty coefficient. The transmission power is obtained through the genetic algorithm. The global optimal solution _opt; (5) The host computer software sends a command to the excitation source to set its power to _opt, get The RSSI values ​​of all tag reflection signals read at _opt power are calculated, and the average RSSI value is obtained, that is, the average optimal , when reading later, fine-tune the excitation source transmission power on this basis to make the overall RSSI value consistent with the RSSI optimal value The average deviation value is less than the threshold ,Right now , The value of is determined according to the actual scenario; According to the formula - ； in, is the number of labels, For the Tags value; like , , the power remains unchanged; like , , The power decreases, The power increases; like , , The power decreases, The power increases; in, is the adjusted power value, is the power value before adjustment, 、 The power adjustment threshold is determined according to actual test. After adjustment, the host computer software will set the excitation source power to .

6. A system for use with the method according to any one of claims 1 to 4, characterized in that: The system includes an electronic tag module, an RFID reader module, an excitation source module and a host computer module; The electronic tag module includes an RFID antenna and an energy harvesting antenna; The RFID reader module includes a reader antenna, the excitation source module includes an excitation source antenna, and the host computer is communicatively connected to the RFID reader module and the excitation source module at the same time; The reader sends a read instruction to the RFID tag through the reader antenna to read the RFID tag information; The excitation source antenna uses an ISM frequency band 5.8 GHz signal to transmit a 5.8 GHz continuous electromagnetic wave signal to the electronic tag module.

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