Numerical Simulation of Crosstalk Effects in PMUT Arrays

The significant negative influence of crosstalk among the diaphragms of Piezoelectric Micromachined Ultrasonic Transducers (PMUT) drives its mechanical and acoustic behavior to deviate from the desired ideal performance. Crosstalk analysis on a 4 × 4 PMUT array designed for in-air applications is presented in this study. It is suspected that crosstalk occurs primarily through acoustic coupling among transducers, or more precisely, through the acoustically connected cavities. A comprehensive set of numerical models representing two adjacent PMUTs working under varying levels of acoustic coupling is investigated in order to understand the level of acoustic crosstalk through the cavities and its impact on the array performance. The numerical results are then validated with experimental data. The computed response spectra of the PMUTs reveal that the presence of secondary peaks, which indicate the presence of crosstalk, is reduced when the transducers are partially or entirely decoupled as compared to a fully coupled case.