Dielectric Tunable Thin-Film Temperature Sensor Based on Microwave Backscatter
LU Fei;TAN Qiulin;North University of China,Science and Technology on Electronic Test and Measurement Laboratory,North University of China;
A wireless passive thin-film temperature sensor is designed aiming at the requirements for surface temperature measurement. The sensor has a metal-patch based "sandwich "profile,which is fabricated with high temperature resistant HTCC( high temperature co-fired ceramics) zirconia and Ag metal layer. A high temperature resistant microstrip antenna is used to test the sensor under high temperature. The relationship between the return loss of the antenna and the frequency is read through a vector network analyzer. It is concluded that the resonant frequency of the sensor is decreased with the increase of the temperature,which is caused by the increased dielectric constant of the temperature-sensitive zirconia with increased temperature. The temperature measurement is achieved at 25 ℃ ～ 700 ℃,and the average sensitivity of the sensor is calculated to be 96.63 kHz/℃. The thin-film temperature sensor designed in this paper has the advantages of high Q factor,low profile and simple structure.