UHF tag chip impedance matching adaptive dynamic adjustment method and device

Abstract

The invention discloses a UHF tag chip impedance matching self-adaptive dynamic adjustment method and device, and relates to the field of radio frequency identification, and the method comprises the following steps: dividing a frequency range into a plurality of frequency bands based on the preset impedance matching frequency range, and obtaining the cut-off frequency of each stage of low-pass filter in a low-pass filter group through the plurality of frequency bands; according to the center frequency of the plurality of frequency bands, capacitor bank data used for impedance matching of the tag chip are obtained, a low-pass filter bank is used for filtering the received radio frequency carrier signals, and step-by-step judgment is carried out on the filtered signals to obtain a judgment result; and performing digital logic processing on the judgment result to obtain a control signal of the capacitor bank, and rematching the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor bank data. Through step-by-step judgment and digital logic processing, the phenomenon of offset of impedance matching between the tag chip and the tag antenna can be effectively inhibited.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency identification, and in particular to a method and a device for adaptively and dynamically adjusting impedance matching of a UHF tag chip. Background Art

[0002] Radio Frequency Identification (RFID) technology is a wireless identification technology. Its basic principle is to use radio frequency to achieve target recognition and obtain data between the reader and the tag. It is considered to be one of the most promising information technologies at present. RFID technology is widely used in various fields such as logistics management, transportation, anti-counterfeiting and identity recognition. Compared with other identification technologies such as QR code and barcode, RFID technology has significant advantages. It does not require direct contact with the object and can achieve complete automatic recognition. It can be used in complex environments and has a longer reading distance and higher reading efficiency.

[0003] For passive UHF RFID (ultra-high frequency radio frequency identification) systems, the most important indicator for measuring their performance is the working distance of the tag. The factors that limit the maximum working distance of the tag include the tag's own performance, the transmission environment, and the reader's performance parameters. In the design process of passive UHF RFID tags, the sensitivity of the tag chip is one of the important factors affecting the working distance, and the chip's sensitivity is mainly affected by the chip's RF front-end circuit structure and manufacturing process. The impedance matching circuit in the chip's RF front-end circuit directly affects the tag's working distance. Only when the impedance conjugate matching between the tag antenna and the chip is guaranteed, can the RF signal power be transmitted to the maximum, thereby maximizing the tag's reading distance at the minimum sensitivity.

[0004] In the UHF RFID tag design process, we generally give the impedance parameters of the chip at a specific frequency, and the tag antenna design is also based on the chip impedance parameters at this frequency. However, in the actual working environment, due to different readers, the carrier frequency actually received by the tag is different from the specific frequency given, which will cause the impedance matching between the antenna and the chip to be destroyed, reduce the transmission power of the RF signal, and further affect the maximum reading distance of the tag. In summary, the existing technology has the problem that the actual working carrier frequency is different from the impedance matching frequency given for reference when designing the antenna, causing the impedance matching between the tag antenna and the chip to change, reducing the transmission power of the RF signal.

[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0006] In view of the problems in the related art, the present invention proposes a method and device for adaptive dynamic adjustment of impedance matching of a UHF tag chip to overcome the above technical problems existing in the existing related art.

[0007] To this end, the specific technical solution adopted by the present invention is as follows:

[0008] According to one aspect of the present invention, a method for adaptive dynamic adjustment of impedance matching of a UHF tag chip is provided, the method comprising the following steps:

[0009] S1. Based on a frequency range of a predetermined impedance matching, the frequency range is divided into a plurality of frequency bands, and the cutoff frequencies of the low-pass filters at each level in the low-pass filter group are obtained through the plurality of frequency bands;

[0010] S2. According to the center frequencies of several frequency bands, the data of the capacitance group used for impedance matching of the tag chip is obtained, and the received radio frequency carrier signal is filtered by a low-pass filter group, and the filtered signal is judged step by step to obtain the judgment result;

[0011] S3. Perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

[0012] Furthermore, the method of obtaining the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through a plurality of frequency bands is: taking the upper frequency limit of the corresponding frequency band as the cutoff frequency of the low-pass filter in the low-pass filter group.

[0013] Furthermore, the method of obtaining the capacitance group data of the tag chip for impedance matching according to the center frequencies of the plurality of frequency bands, filtering the received radio frequency carrier signal by using a low-pass filter group, and making step-by-step judgments on the filtered signal to obtain the judgment result includes the following steps:

[0014] S21. Based on the divided frequency bands, the center frequency of each frequency band is obtained, and the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching is calculated using the center frequency when the tag antenna inductance remains unchanged;

[0015] S22, using the equivalent capacitance to calculate the additional capacitance required for impedance matching, and obtaining capacitance group data of the tag chip for impedance matching according to the additional capacitance;

[0016] S23, rectifying the radio frequency carrier signal received by the tag chip into a DC signal through a half-wave rectifier, connecting the DC signal to a low-pass filter group for filtering, and performing step-by-step judgment on the signals filtered by each level of low-pass filters to obtain a judgment result.

[0017] Furthermore, the calculation formula of the equivalent capacitance is:

[0018]

[0019] Wherein, f represents the center frequency of the frequency band; L represents the equivalent inductance of the tag antenna; C' represents the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at the frequency f.

[0020] Furthermore, the calculation formula of the additional incorporated capacitance is:

[0021] C x = C'-C;

[0022] In the formula, C x Indicates that an additional capacitor needs to be incorporated; C indicates a predetermined equivalent capacitance; C' indicates the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at a frequency of f.

[0023] Furthermore, the step-by-step decision rule for the signals filtered by the low-pass filters at each level is:

[0024] If the signal after low-pass filter filtering contains a radio frequency carrier signal, the output judgment result is binary 1;

[0025] If the signal after low-pass filter filtering has no RF carrier signal, the output judgment result is binary 0.

[0026] Furthermore, the digital logic processing of the judgment result to obtain the control signal of the capacitor group, and re-matching the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data includes:

[0027] S31, performing digital logic processing on the judgment result to obtain the result of the requirement for additional incorporation of capacitors;

[0028] S32, converting the result of the additional capacitor requirement into a control signal of an impedance matching adjustment circuit to obtain an access signal of the additional capacitor;

[0029] S33. Based on the access signal of the additional capacitor and in combination with the capacitor group data, the additional capacitor is accessed to match the impedance of the tag chip and the tag antenna.

[0030] Furthermore, the processing rule for performing digital logic processing on the judgment result to obtain the result of the requirement for additional incorporation of capacitors is:

[0031] If the output judgment results of the current low-pass filter and the previous low-pass filters are both binary 1, and the output judgment results of the subsequent low-pass filters are both binary 0, then there is a need to incorporate additional capacitors corresponding to the frequency band of the current low-pass filter;

[0032] If the output judgment results of each level of low-pass filter are all binary 0, there is no need to incorporate additional capacitors.

[0033] Furthermore, the method of converting the demand result of the additionally incorporated capacitor into a control signal of the impedance matching adjustment circuit to obtain an access signal of the additionally incorporated capacitor includes: converting the demand result of the additionally incorporated capacitor into a switch signal for controlling the access of the additionally incorporated capacitor in the impedance matching adjustment circuit to obtain an access signal of the capacitor group.

[0034] According to another aspect of the present invention, a UHF tag chip impedance matching adaptive dynamic adjustment device is provided, and the UHF tag chip impedance matching adaptive dynamic adjustment device comprises: a frequency band division module, a step-by-step decision module and an impedance matching module;

[0035] The frequency band division module is used to divide the frequency range into a plurality of frequency bands based on a predetermined frequency range of impedance matching, and obtain the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through the plurality of frequency bands;

[0036] The step-by-step decision module is used to obtain the capacitance group data used for impedance matching of the tag chip according to the center frequencies of several frequency bands, and to filter the received radio frequency carrier signal using a low-pass filter group, and to make step-by-step decisions on the filtered signal to obtain a decision result;

[0037] The impedance matching module is used to perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

[0038] The beneficial effects of the present invention are:

[0039] The present invention dynamically adjusts the impedance matching changes caused by the carrier frequency through a low-pass filter group, step-by-step judgment and digital logic processing, ensuring that when the actual operating frequency of the tag chip is different from the impedance matching reference frequency when designing the tag antenna, the impedance matching deviation between the tag chip and the tag antenna can be effectively suppressed, thereby improving the transmission power of the radio frequency signal and improving the compatibility of the UHF (ultra-high frequency) tag chip with different operating frequencies; realizing dynamic adjustment of the impedance matching of the UHF tag chip and the tag antenna, and improving the transmission power of the radio frequency signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 is a flow chart of a method for adaptively and dynamically adjusting impedance matching of a UHF tag chip according to an embodiment of the present invention;

[0042] Figure 2 This is a principle block diagram of a UHF tag chip impedance matching adaptive dynamic adjustment device according to an embodiment of the present invention;

[0043] Figure 3 It is a general framework diagram of a method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to an embodiment of the present invention;

[0044] Figure 4 A low-pass filter group model in a method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to an embodiment of the present invention;

[0045] Figure 5 The invention discloses an impedance matching capacitor group model in a method for adaptively and dynamically adjusting impedance matching of a UHF tag chip according to an embodiment of the present invention.

[0046] In the figure:

[0047] 1. Frequency band division module; 2. Step-by-step decision module; 3. Impedance matching module. DETAILED DESCRIPTION

[0048] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention.

[0049] According to an embodiment of the present invention, a method and device for adaptive dynamic adjustment of impedance matching of a UHF tag chip are provided.

[0050] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 According to an embodiment of the present invention, a method for adaptive dynamic adjustment of impedance matching of a UHF tag chip is provided, and the method comprises the following steps:

[0051] S1. Based on a frequency range of a predetermined impedance matching, the frequency range is divided into a plurality of frequency bands, and the cutoff frequencies of the low-pass filters at each level in the low-pass filter group are obtained through the plurality of frequency bands.

[0052] Specifically, the method of obtaining the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through a plurality of frequency bands is: taking the upper frequency limit of the corresponding frequency band as the cutoff frequency of the low-pass filter in the low-pass filter group.

[0053] S2. According to the center frequencies of several frequency bands, the data of the capacitor group used for impedance matching of the tag chip is obtained, and the received RF carrier signal is filtered by a low-pass filter group, and the filtered signal is judged step by step to obtain the judgment result.

[0054] Specifically, the method of obtaining the capacitance group data of the tag chip for impedance matching according to the center frequencies of several frequency bands, filtering the received radio frequency carrier signal by using a low-pass filter group, and making step-by-step judgments on the filtered signal to obtain the judgment result includes the following steps:

[0055] S21. Based on the divided frequency bands, the center frequency of each frequency band is obtained, and the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching is calculated using the center frequency when the tag antenna inductance remains unchanged;

[0056] S22, using the equivalent capacitance to calculate the additional capacitance required for impedance matching, and obtaining capacitance group data of the tag chip for impedance matching according to the additional capacitance;

[0057] S23, rectifying the radio frequency carrier signal received by the tag chip into a DC signal through a half-wave rectifier, connecting the DC signal to a low-pass filter group for filtering, and performing step-by-step judgment on the signals filtered by each level of low-pass filters to obtain a judgment result.

[0058] Specifically, the calculation formula of the equivalent capacitance is:

[0059]

[0060] Wherein, f represents the center frequency of the frequency band; L represents the equivalent inductance of the tag antenna; C' represents the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at the frequency f.

[0061] Specifically, the calculation formula of the additional incorporated capacitance is:

[0062] C x = C'-C;

[0063] In the formula, C x Indicates that an additional capacitor needs to be incorporated; C indicates a predetermined equivalent capacitance; C' indicates the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at a frequency of f.

[0064] Specifically, the rule for making a step-by-step decision on the signal after filtering by each level of low-pass filter is:

[0065] If the signal after low-pass filter filtering contains a radio frequency carrier signal, the output judgment result is binary 1;

[0066] If the signal after low-pass filter filtering has no RF carrier signal, the output judgment result is binary 0.

[0067] S3. Perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

[0068] Specifically, the digital logic processing of the judgment result to obtain the control signal of the capacitor group, and re-matching the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data includes:

[0069] S31, performing digital logic processing on the judgment result to obtain the result of the requirement for additional incorporation of capacitors;

[0070] S32, converting the result of the additional capacitor requirement into a control signal of an impedance matching adjustment circuit to obtain an access signal of the additional capacitor;

[0071] S33. Based on the access signal of the additional capacitor and in combination with the capacitor group data, the additional capacitor is accessed to match the impedance of the tag chip and the tag antenna.

[0072] Specifically, the digital logic processing of the judgment result to obtain the processing rule of the additional capacitor requirement result is:

[0073] If the output judgment results of the current low-pass filter and the previous low-pass filters are both binary 1, and the output judgment results of the subsequent low-pass filters are both binary 0, then there is a need to incorporate additional capacitors corresponding to the frequency band of the current low-pass filter;

[0074] If the output judgment results of each level of low-pass filter are all binary 0, there is no need to incorporate additional capacitors.

[0075] Specifically, the method of converting the demand result of the additionally incorporated capacitor into a control signal of the impedance matching adjustment circuit to obtain the access signal of the additionally incorporated capacitor includes: converting the demand result of the additionally incorporated capacitor into a switch signal for controlling the access of the additionally incorporated capacitor in the impedance matching adjustment circuit to obtain the access signal of the capacitor group.

[0076] like Figure 2 As shown, according to another embodiment of the present invention, a UHF tag chip impedance matching adaptive dynamic adjustment device is provided, and the UHF tag chip impedance matching adaptive dynamic adjustment device includes: a frequency band division module, a step-by-step decision module and an impedance matching module;

[0077] The frequency band division module 1 is used to divide the frequency range into a plurality of frequency bands based on a predetermined frequency range of impedance matching, and obtain the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through the plurality of frequency bands;

[0078] The step-by-step decision module 2 is used to obtain the capacitance group data used for impedance matching of the tag chip according to the center frequencies of several frequency bands, and to filter the received radio frequency carrier signal using a low-pass filter group, and to make step-by-step decisions on the filtered signal to obtain a decision result;

[0079] The impedance matching module 3 is used to perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

[0080] In summary, the present invention is composed of a half-wave rectifier group 101, a low-pass filter group 102, a step-by-step decision 103, a digital logic module 104 and an impedance matching capacitor group 105; wherein the low-pass filter group and the step-by-step decision are used to confirm the frequency band of the carrier frequency actually received by the UHF tag, and the digital logic processing and the impedance matching adjustment capacitor group jointly complete the dynamic adjustment of the impedance matching of the UHF tag chip and the tag antenna (the specific overall framework is as follows Figure 3 shown).

[0081] For example, taking the equivalent capacitance C

[304] of the impedance of a given tag chip at 950MHz as an example, the equivalent inductance of the antenna designed based on this equivalent capacitance C is L ANT

[302] , R ANT

[301] is the equivalent resistance of the antenna, R ref

[303] is the equivalent resistance of the chip (such as Figure 5 shown).

[0082] The frequency range based on the predetermined impedance matching is divided into a plurality of frequency bands, and the cutoff frequencies of the low-pass filters at each level in the low-pass filter group are obtained through the plurality of frequency bands. Specifically, 860MHz-960MHz is divided into five frequency bands: 960MHz-940MHz, 940MHz-920MHz, 920MHz-900MHz, 900MHz-880MHz, and 880MHz-860MHz. Therefore, the cutoff frequencies of the four low-pass filters LF1

[201] , LF2

[202] , LF3

[203] , and LF4

[204] in the low-pass filter group are 940MHz, 920MHz, 900MHz, and 880MHz, respectively. The low-pass filter group of this embodiment is as follows: Figure 4 shown.

[0083] According to the center frequencies of several frequency bands, the data of the capacitor group used for impedance matching of the tag chip is obtained, specifically: the center frequencies corresponding to each frequency band are 950MHz, 930MHz, 910MHz, 890MHz, and 870MHz respectively; according to the calculation formula of the equivalent capacitance and the calculation formula of the additional incorporated capacitance, in the calculation formula of the equivalent capacitance, f is the center frequency except 950MHz in the above, L is the equivalent inductance of the antenna, C' is the equivalent capacitance when the chip and the antenna achieve conjugate matching at the frequency f, and C in the calculation formula of the additional incorporated capacitance is x is the capacitor that needs to be incorporated; it can be calculated that the capacitor C1

[301] that should be additionally incorporated into the impedance matching network at 930MHz, the capacitor C2

[302] that should be additionally incorporated into the impedance matching network at 910MHz, the capacitor C3

[303] that should be additionally incorporated into the impedance matching network at 890MHz, and the capacitor C4

[304] that should be additionally incorporated into the impedance matching network at 870MHz. The impedance matching capacitor group of this example is as follows Figure 5 shown.

[0084] The low-pass filter group is used to filter the received RF carrier signal, and the filtered signal is judged step by step to obtain the judgment result, which is specifically: the RF carrier actually received by the UHF tag is connected to the half-wave rectifier group 101, and is half-wave rectified into a DC signal. The rectified DC signal enters the low-pass filter group (such as Figure 5 As shown) and make decisions step by step. In the figure, switches S1

[309] , S2

[310] , S3

[311] , and S4

[312] are all switches controlled by digital logic.

[0085] The step-by-step judgment is specifically to judge the signal after filtering through each level of low-pass filter. If there is still a carrier signal, a high level is output, that is, digital logic "1"; if there is no carrier signal, a low level is output, that is, digital logic "0". Therefore, the four-level low-pass filter group will output four judgment results such as "1111", and then perform digital logic processing.

[0086] The digital logic processing is specifically as follows: if the input judgment result is "0000", no additional capacitor is required; if the input is "1000", the switch S1

[309] is closed, and only the capacitor C1

[305] is connected; if the input is "1100", the switch S2

[310] is closed, and only the capacitor C2

[306] is connected; if the input is "1110", the switch S3

[311] is closed, and only the capacitor C3

[307] is connected; if the input is "1111", the switch S4

[312] is closed, and only the capacitor C4

[308] is connected.

[0087] After the capacitor is connected, the impedance matching between the UHF tag chip and the tag antenna changes. The influence of the impedance matching offset caused by the difference between the actual working frequency and the reference frequency when designing the antenna is suppressed, and the power of the RF signal increases.

[0088] The impedance matching adjustment circuit is specifically: a power supply V ANT The positive electrode and the resistor R ANT Connect one end of the resistor R ANT The other end of the inductor L ANT One end of the inductor L ANT The other end of the resistor R ref Connect one end of the resistor R ref The other end of capacitor C is connected to one end of capacitor C1, capacitor C2, capacitor C3 and capacitor C4 respectively, the other end of capacitor C1 is connected to one end of switch S1, the other end of capacitor C2 is connected to one end of switch S2, the other end of capacitor C3 is connected to one end of switch S3, the other end of capacitor C4 is connected to one end of switch S4, the other end of capacitor C is connected to the other ends of switch S1, switch S2, switch S3, switch S4 and one end of ground GND respectively, and the other end of ground GND is connected to power supply V ANT Negative connection (such as Figure 5 shown).

[0089] To sum up, with the help of the above-mentioned technical scheme of the present invention, the present invention dynamically adjusts the impedance matching changes caused by the carrier frequency through a low-pass filter group, step-by-step judgment and digital logic processing, ensuring that when the actual operating frequency of the tag chip is different from the impedance matching reference frequency when designing the tag antenna, the impedance matching between the tag chip and the tag antenna is effectively suppressed. The offset phenomenon, thereby improving the transmission power of the RF signal and improving the compatibility of the UHF (ultra-high frequency) tag chip with different operating frequencies; realizing the dynamic adjustment of the impedance matching of the UHF tag chip and the tag antenna, and improving the transmission power of the RF signal.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for adaptive dynamic adjustment of impedance matching of a UHF tag chip, characterized in that: The method comprises the following steps: S1. Based on a frequency range of a predetermined impedance matching, the frequency range is divided into a plurality of frequency bands, and the cutoff frequencies of the low-pass filters at each level in the low-pass filter group are obtained through the plurality of frequency bands; S2. According to the center frequencies of several frequency bands, the data of the capacitance group used for impedance matching of the tag chip is obtained, and the received radio frequency carrier signal is filtered by a low-pass filter group, and the filtered signal is judged step by step to obtain the judgment result; S3. Perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

2. A UHF tag chip impedance matching adaptive dynamic adjustment method according to claim 1, characterized in that: The method of obtaining the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through a plurality of frequency bands is: taking the upper frequency limit of the corresponding frequency band as the cutoff frequency of the low-pass filter in the low-pass filter group.

3. The method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 1, characterized in that: The method of obtaining the capacitance group data of the tag chip for impedance matching according to the center frequencies of the plurality of frequency bands, filtering the received radio frequency carrier signal by using a low-pass filter group, and making step-by-step judgments on the filtered signal to obtain the judgment result includes the following steps: S21. Based on the divided frequency bands, the center frequency of each frequency band is obtained, and the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching is calculated using the center frequency when the tag antenna inductance remains unchanged; S22, using the equivalent capacitance to calculate the additional capacitance required for impedance matching, and obtaining capacitance group data of the tag chip for impedance matching according to the additional capacitance; S23, rectifying the radio frequency carrier signal received by the tag chip into a DC signal through a half-wave rectifier, connecting the DC signal to a low-pass filter group for filtering, and performing step-by-step judgment on the signals filtered by each level of low-pass filters to obtain a judgment result.

4. A UHF tag chip impedance matching adaptive dynamic adjustment method according to claim 3, characterized in that: The calculation formula of the equivalent capacitance is: Wherein, f represents the center frequency of the frequency band; L represents the equivalent inductance of the tag antenna; C' represents the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at the frequency f.

5. The method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 3 is characterized in that: The calculation formula for the additional incorporated capacitance is: C x =C'-C; In the formula, C x Indicates that an additional capacitor needs to be incorporated; C indicates a predetermined equivalent capacitance; C' indicates the equivalent capacitance when the tag chip and the tag antenna achieve impedance conjugate matching at a frequency of f.

6. The method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 3, characterized in that: The step-by-step decision rule for the signals filtered by the low-pass filters at each level is: If the signal after low-pass filter filtering contains a radio frequency carrier signal, the output judgment result is binary 1; If the signal after low-pass filter filtering has no RF carrier signal, the output judgment result is binary 0.

7. A method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 6, characterized in that: The step of performing digital logic processing on the judgment result to obtain a control signal of the capacitor group, and re-matching the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data includes: S31, performing digital logic processing on the judgment result to obtain the result of the requirement for additional incorporation of capacitors; S32, converting the result of the additional capacitor requirement into a control signal of an impedance matching adjustment circuit to obtain an access signal of the additional capacitor; S33. Based on the access signal of the additional capacitor and in combination with the capacitor group data, the additional capacitor is accessed to match the impedance of the tag chip and the tag antenna.

8. A method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 7, characterized in that: The processing rule for performing digital logic processing on the judgment result to obtain the result of the requirement for additional incorporation of capacitors is: If the output judgment results of the current low-pass filter and the previous low-pass filters are both binary 1, and the output judgment results of the subsequent low-pass filters are both binary 0, then there is a need to incorporate additional capacitors corresponding to the frequency band of the current low-pass filter; If the output judgment results of each level of low-pass filter are all binary 0, there is no need to incorporate additional capacitors.

9. The method for adaptive dynamic adjustment of impedance matching of a UHF tag chip according to claim 7, characterized in that: The method of converting the demand result of the additionally incorporated capacitor into a control signal of the impedance matching adjustment circuit to obtain the access signal of the additionally incorporated capacitor includes: converting the demand result of the additionally incorporated capacitor into a switch signal for controlling the access of the additionally incorporated capacitor in the impedance matching adjustment circuit to obtain the access signal of the capacitor group.

10. A UHF tag chip impedance matching adaptive dynamic adjustment device, used to implement the UHF tag chip impedance matching adaptive dynamic adjustment method according to any one of claims 1 to 9, characterized in that: The UHF tag chip impedance matching adaptive dynamic adjustment device comprises: a frequency band division module, a step-by-step decision module and an impedance matching module; The frequency band division module is used to divide the frequency range into a plurality of frequency bands based on a predetermined frequency range of impedance matching, and obtain the cutoff frequencies of the low-pass filters at each level in the low-pass filter group through the plurality of frequency bands; The step-by-step decision module is used to obtain the capacitance group data used for impedance matching of the tag chip according to the center frequencies of several frequency bands, and to filter the received radio frequency carrier signal using a low-pass filter group, and to make step-by-step decisions on the filtered signal to obtain a decision result; The impedance matching module is used to perform digital logic processing on the judgment result to obtain the control signal of the capacitor group, and re-match the impedance of the tag chip and the tag antenna by combining the control signal with the capacitor group data.

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