Force-frequency effect of thickness mode langasite resonators

Langasite resonators are of recent interest for a variety of applications because of their good temperature behavior, good piezoelectric coupling, low acoustic loss and high Q factor. The force-frequency effect describes the shift in resonant frequency a resonator experiences due to the application of a mechanical load. A clear understanding of this effect is essential for many design applications such as pressure sensors. In this article, the frequency shift is analyzed theoretically and numerically for thin, circular langasite plates subjected to a pair of diametrical forces. In addition, the sensitivity of the force-frequency effect is analyzed with respect to the nonlinear material constants. The results are anticipated to be valuable for experimental measurements of nonlinear material constants as well as for device design.