Sensitivity analysis of langasite surface acoustic wave pressure sensors

Langasite (La3Ga5SiO14, LGS) surface acoustic wave (SAW) pressure sensors can be applied to harsh enviroments above 500°C. The pressure sensitivity has significant effects on the accuracy of pressure measurement. The optimization of pressure sensitivity based on some factors such as substrate cuts and packaging structures has been reported. However, there is no report about the comprehensive influence of sealed cavity size and SAW sensor position on the pressure sensitivity for different cuts. In this paper, the SAW pressure sensitivity was simulated by combining the finite element method (FEM) and the perturbation theory to analyze the influence of the shape and size of sealed cavities, and sensor positions with different substrate cuts based on face pressing structure. As a result, these factors affected the sensitivity comprehensively. Thus, it is helpful to take more factors into account to improve sensitivity.