Temperature/Pressure/Humidity Coplanar Integrated SAW Sensor Based on LGS

Abstract

In this paper, a three-parameter coplanar-integrated surface acoustic wave sensor based on Langasite is proposed. The micro-scale multi-parameter coplanar Temperature-Pressure-Humidity (TPH) sensor was developed by Micro-Electro-Mechanical System (MEMS) techniques such as wet etching, hot pressing bonding, and lifting off. The Mxene@ MoS2@Go (MMG) composite material was used as the humidity-sensitive material to enlarge the range of the humidity test and improve the sensitivity of the sensor test, and the humidity-sensitive unit shows high performance with a fast response time (3.18 s) and recovery time (0.94 s). The TPH sensor has been tested, and the experimental results indicate that the sensor can operate steadily at 25–700°C, 0-700 kPa, and 10–98% RH. Besides, a temperature decoupling approach is presented to address the issue of multi-parameter mutual coupling and improve the measurement accuracy of the sensitive unit while measuring several parameters at the same time. These excellent results are attributed to the coupling between many parameters in complex environments. Also, our work can be applied to the simultaneous measurement of several parameters in challenging conditions.