Test and Analysis of SAW High Temperature Strain Sensor Based on Langasite

In this study, we fabricate a surface acoustic wave strain sensor based on langasite. By constructing a temperature-strain composite testing platform, we examine this sensor for the strains of 0 to 500 $\mu \varepsilon $ at temperatures ranging from 18 to $700~^{\circ }\text{C}$ . The value obtained from the tests for the strain sensitivity of the sensor is 20.09 Hz/ $\mu \varepsilon $ at 700 °C, and the maximum relative error and hysteresis error are 3.35% and 6.98%, respectively. Moreover, the sensor exhibits a stable response at high temperatures. Considering the sensitivity of the temperature and strain of the sensor at high temperatures, a temperature - strain decoupling method is proposed. The strain values obtained after the calculation agreed well with the reference strain values, and the maximum error was between −4.2% and 5.425%. Therefore, the proposed temperature - strain decoupling method could help eliminate the influence of temperature on the strain measurements of this sensor.