Langasite crystal based pressure sensor with temperature compensation

This paper presents the design and testing of a new pressure sensor utilizing a doubly rotated cut piezoelectric langasite (LGS) crystal resonator with temperature compensation. The sensor can measure temperature and pressure simultaneously by using the dual mode nature of the doubly rotated cut langasite resonator (SBTC). The sensor is designed using CAD software, fabricated and tested experimentally in the laboratory for a pressure range from 0 to 45 PSI. Before fabrication the sensing principle was verified performing a force frequency analysis on the langasite resonator using a special apparatus. The experimental results on the sensor show a good linear relationship between applied pressure and C-mode frequency. Temperature compensation is also achieved by utilizing the dual mode behavior of the LGS crystal resonator. The comparison between our experiment and Peer's theoretical modelling results shows a reasonable consistency. The sensor structure is very compact, robust, low cost and temperature compensation can be achieved at high temperatures particularly in nuclear applications.