Research And Design Of Passive High Frequency RFID Front End Chip With Integrated Temperature Sensor

With the popularazation of wireless network and smart devices,the concept of IOT technology is developing rapidly.As an important component of IOT,RFID has broad application prospects.RFID system with integrated temperature sensor will further expand its application range,.This thesis focus on research of passive HF RFID front end circuit with integrated temperature sensor.,and designs the RF analog front-end circuit and temperature sensor.Firstly,this thesis studies the energy and data transmission methods of the high-frequency RFID system,as well as the mainstream structure of the temperature sensor.The correlation between the RF analog front-end circuit and the temperature sensor is analyzed.On this basis,the system structure of a passive high-frequency RFID analog front-end chip with integrated temperature sensor is proposed.Secondly,the design of the RF analog front-end circuit is introduced in detail,including the rectifier circuit,voltage regulator circuit,modulation circuit,demodulation circuit and clock circuit.The rectifier circuit adopting NMOS gate cross structure is proposed,the PCE of it is more than 54.98%;The voltage regulator circuit generates a stable voltage of 1.8V,while the linear adjustment rate is less than 1%,and the maximum load current can reach 1m A.Thirdly,a temperature sensor suitable for passive high-frequency RFID tags is proposed,including three parts: temperature sensing circuit,voltage buffer and SAR ADC.The temperature sensing circuit has a built-in programmable resistor,which reduces the influence of process fluctuations.The 11 bit SAR ADC uses a monotonic switching strategy to reduce power consumption.The sampling rate of it is 22KS/s and the power consumption at 1.8V is34.02?W.Simulation reasult shows that,the inaccuracy of the temperature sensor is about ±0.2? in the range of-25? ?-50?,±1? in 50 ? ? 70 ?.When the temperature is higher than 70 ?,the inaccuracy exceeds 1 ?Finally,a passive high-frequency RFID analog front-end chip with integrated temperature sensor was fabricated in the SMIC 0.18?m EEPROM process.The test result shows that the Chip can communicate with Reader at a data rate of 106 Kbps,the antenna signal modulation depth reached 66.7%.In the meantime,it generates the stable supply voltage,clock and reset signals.The temperature inaccuracy of the temperature sensor in the temperature range of 9?? 41? is ±1?.