Force-frequency effect of thickness mode langasite resonators

Abstract

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 presentation, the frequency shift is analyzed theoretically and numerically for thin, circular langasite plates subjected to a diametrical force. The results are compared with experimental measurements of the same system for a variety of langasite resonators with various material orientations. In addition, the sensitivity of force-frequency effect is analyzed with respect to the nonlinear material constants. A comparison between the force-frequency effect of langasite and quartz resonators is also made. Finally, the application of such measurements for determining third-order elastic constants is discussed. [Work supported by ARO.]