Hardware Design of RF Temperature Measurement Transceiver System Based on Delayed Linear SAW Temperature Sensor

Abstract

This article first studies the working principle of a wireless passive SAW (Surface Acoustic Wave) temperature sensor. The pulse query signal is used to excite the sensor. After the sensor is excited, it returns the pulse signal reflected by each reflector. By measuring the phase difference of the pulse signals returned by the reflectors inside the sensor, the temperature of the sensor is estimated by the phase difference. The measurement scheme is given according to the principle of the sensor, and a matching RF temperature measurement system is designed based on the FPGA as the main control chip. The test results show that the temperature measurement system designed in this paper has a temperature measurement range of $25^{\circ}\mathrm{C}-130^{\circ}\mathrm{C}$, a measurement error of $0.6^{\circ}\mathrm{C}$, and a wireless signal transmission distance between the measurement system and the SAW temperature sensor is 100mm.