Crosstalk Effects in PMUT Arrays

This paper investigates the effect of crosstalk among the diaphragms of a 4 x 4 Piezoelectric Micromachined Ultrasonic Transducers (PMUT) array, designed for in-air applications, on its mechanical and acoustic behavior. A comparison of the response spectra of the PMUTs analyzed when operating in vacuum and in air revealed that acoustic coupling, mainly through the air-connected cavities, is the primary cause of crosstalk when compared to electrical and structural coupling. The in-air analysis also revealed that crosstalk could lead to constructive interference among the PMUTs, resulting in pressure emissions at higher intensities. However, its directivity is found to be negatively influenced.