An Efficient Electrode Optimization Method for Multi-Frequency PMUTs

This paper presents a simple and efficient electrode optimization method, which is applicable to any flat PMUT diaphragm shape resonating at any flexural mode. The method exploits the fact that the sensitivity of a PMUT stack is proportional to the sum of in-plane strains of the PMUT diaphragm. The in-vacuo strain mode shapes is obtained from the eigenfrequency finite element method (FEM). The method is applied to elliptical PMUTs with two different aspect ratios having single electrodes and the optimal electrode parameters for the maximum performance at the first three odd flexural modes are obtained. The results show good agreement with those acquired from three-dimensional fully coupled FEM simulations in water.