Electromechanical Performance Comparison for Different Piezoelectric Micromachined Ultrasonic Transducer Element Geometries

Relative performances for three different piezoelectric micromachined ultrasonic transducer (pMUT) element geometries are compared in this work after numerical simulation with a finite element method (FEM) approach. Geometries studied include square, circle and hexagon. Comparisons are presented both for same area and same pitch elements. Obtained results for the main electromechanical parameters describing pMUT behavior include maximum membrane displacement, frequency response, mode shapes and complex impedance. Results indicate significant performance differences between geometries due to the different resonance frequencies affecting the electrodynamics of each system, greater than any possibly incurred numerical error. The square geometry was found to present maximum membrane displacement and highest resonance frequency, followed by the hexagon and the circle.