Radio frequency passive tag capable of being activated and self-tuned for multiple times in real time and method

Abstract

The invention relates to a radio frequency passive tag capable of being activated and self-tuned for multiple times in real time and a method. The tag comprises an antenna, a radio frequency front end, an impedance self-adaptive adjusting module, an analog front end, an EEPROM, a digital baseband, a detection capacitor C11, a switch K and a switch W / L, the antenna is cooperatively coupled with the radio frequency front end, and the radio frequency front end is connected with the detection capacitor C11; the detection capacitor C11 and the radio frequency front end are connected with the impedance adaptive adjustment module through the switch K. The EEPROM is connected with the impedance adaptive adjustment module through the switch W / L. The switch K and the switch W / L are both controlled by the digital baseband. Standard 50 ohm matching is removed, the best matching effect is obtained through conjugate matching, and energy loss is reduced; the digital baseband and the impedance self-adaptive adjusting module can be interacted through a command transmitted by a reader so that the command is reconfigured and activated, matching locking and real-time activation can be carried out for multiple times, and the impedance mismatching condition under the influence of factors such as process and environment within a certain impedance range is solved.

Description

technical field [0001] The invention relates to the field of passive radio frequency, in particular to a radio frequency passive label and method capable of multiple real-time activation of self-tuning. Background technique [0002] With the continuous development and interaction of network communication technology, big data technology, sensing technology and integrated circuit technology, passive IoT node technology that does not require power or battery power has attracted more and more attention. Passive chips and The passive tag technology combined with antennas has become the focus and hot issue of research and application. With the continuous development of system technology, chip technology and antenna integration technology, the application scenarios of passive tags for Internet of Things nodes continue to expand. The integration of data technology and sensing technology gradually develops applications in smart farms, smart homes, environmental monitoring, medical h...

AI Technical Summary

Problems solved by technology

[0003] At present, the research on the energy acquisition of passive tag chips needs to be improved, especially the use of radio frequency energy. The traditional 50Ω matching impedance needs to add various types of matching networks to achieve the highest power transmission. increase the loss

In addition, there are currently antennas that directly use the chip impedance to design the conjugate impedance, which avoids the energy loss caused by the matching network, but the impedance cannot be accurately matched, and the chip impedance is easily affected by environmental factors, process manufacturing factors, etc. Especially for high-sensitivity passive tags, the difference between the impedance and the antenna impedance determines the performance of the tag, and for a large number of tags, it is time-consuming and laborious to perform impedance matching

[0004] At present, there are related technical inventions, such as: an adaptive adjustment method for RFID antenna impedance under harsh working conditions (application number 201610482611.3). The phase difference is relatively complicated, the power consumption of the adjustment process is relatively large, and the clock needs to be provided by FPGA, which is not easy to integrate. The clock requirements on the chip are relatively high; in a radio frequency energy harvesting system based on dynamic impedance matching technology (application number 201610163509.7), it is also aimed at 50 The ohm matching network is adjusted, and the clock requirements are relatively high; in the UHF RFID read-write module (application number 201210505064.8) based on antenna adaptive tuning technology, it requires a central processing unit, and also includes two crystal oscillators to generate clocks, which also It is not suitable for high-sensitivity tags, and it is not easy to integrate because of the existence of the crystal oscillator; the resonant wireless power transmission system and control method capable of self-tuning impedance (application number 201910201498.0), which is designed for 50 ohm matching, the adjustment accuracy is not high, and it is not suitable for specific Impedance, high-sensitivity label adjustment; a π-type impedance automatic matching system and method in a radio frequency energy harvesting circuit (application number 201710267102.3) in which the impedance is adjusted by adjusting the π-type network, the circuit structure and algorithm are complex, and the power consumption is high; a In a passive UHF RFID tag with automatic impedance matching function (application number 201710267093.8), an additional auxiliary voltage doubler rectification unit is added to supply power for the automatic impedance matching network. The additional rectification unit will reduce the sensitivity of the tag , the system collaborative design architecture is not complete enough

[0005] With the development of communication technology, such as 5G communication and new generation communication technology, narrowband communication for IoT nodes is an important part. There are differences, such as passive RFID frequency bands, the United States, Europe, Japan and China have different subdivided frequency bands in the range of 860MHz to 960MHz. In addition, in the manufacturing and packaging of RF antennas and RF chip circuits, there are inevitably The discreteness of processing parameters and the influence of many actual factors such as changes in the product application environment will affect the impedance parameters of the antenna and chip RF interface, resulting in a certain degree of mismatch, affecting product performance or cost

The products M730, M750 series and Monza R6 series of American Passive Label Company have added the function of impedance adjustment, but only use the storage of five impedance states, large-grained active impedance adjustment to adapt to the feedback problems in processing and application, and carry out Impedance adjustment of five states in different scenarios, currently the precision of impedance adjustment is not high

In addition, foreign academic circles have also researched on impedance adjustment, but they are all adjusted based on off-chip clocks. The logic function is more complicated, the power consumption is relatively large, the test and experiment process is too simplified and idealized, and it lacks practicability. Enables high-sensitivity, high-accuracy tuning for passive nodes

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