Fluid-structure interaction modelling of the roof tile-shaped modes in piezoelectric plate microresonators

Abstract

In this paper, the fluid-structure interaction in cantilever-type devices vibrating in the first and higher roof tile-shaped modes is studied. These modes can be most efficiently excited by a thin piezoelectric film on top of the structure in combination with a tailored electrode design. The electrical and optical characterization of the different devices and modes is carried out in liquid media and then the performance of the resonators is evaluated in terms of quality factor and resonant frequency. The effect of the fluid on the in-liquid response is studied using analytical and finite element method models. For the latter, a fully coupled fluid-structure interaction model is developed and compared to a simpler model, in which no coupling feedback from the fluid to the structure is taken into account. The results show that, despite the substantially larger computational effort, the consideration of the fluid-structure coupling is absolutely necessary to explain the experimental results for higher order modes.