Radio frequency energy acquisition system based on energy management and passive radio frequency tag

Abstract

The invention relates to a radio frequency energy acquisition system based on energy management and a passive radio frequency tag. The system comprises an antenna, a radio frequency front end, an impedance adaptive adjustment module, a load isolation and charge-discharge control module, a linear voltage stabilization module, a switch K, a detection capacitor C11 and an energy storage capacitor C12. The antenna is cooperatively coupled with the radio frequency front end; the output end of the radio frequency front end is connected with one end of the detection capacitor C11; and the output end of the radio frequency front end is further connected with one end of an energy storage capacitor C12 and a load isolation and charge-discharge control module through a switch K, the other end of the detection capacitor C11 and the other end of the energy storage capacitor C12 are both grounded, and the switch K is controlled by an impedance self-adaptive adjustment module. Standard 50 omega matching is removed, conjugate matching is adopted to obtain the optimal matching effect, and it is ensured that the state is still in the optimal matching state after state switching through load isolation; and stable power supply voltage is output in a pre-charging and voltage stabilizing mode, and efficient utilization of energy is achieved.

Description

technical field [0001] The invention relates to the field of passive radio frequency, in particular to a radio frequency energy acquisition system based on energy management and a passive radio frequency tag. 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 supply or battery power has attracted more and more attention. The passive tag technology combined with antenna 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 labels used in IoT nodes are expanding. , the integration of data technology and sensing technology, and gradually develop applications in smart farms, smart homes, environmental monitoring, medical and health and ...

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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