Design, modelling, and characterization of display compatible pMUT device

Abstract

In this paper, the design, modeling, and characterization of a display compatible pMUT platform are presented. A FEM model is built using COMSOL Multiphysics for evaluating the frequency response, mechanical performance, acoustic pressure, and driving efficiency of our pMUT device across all vibration modes of circular plates. In parallel with it, a first mode analytical model has been developed including electrical, mechanical, and acoustic domains to provide fast estimation for future design. A laser Doppler vibrometer is used to measure the frequency response, displacement, velocity as well as mode shapes of pMUTs with different designs in air. The measured resonance frequency of first mode range from 121.5kHz to 1.1MHz with radius from 500μm to 120μm and fits the prediction of FEM and analytical models. A standard reference microphone is used to measure the acoustic pressure of pMUT inside its frequency range (<125 kHz). The measured acoustic pressure on transverse axis of a 500μm radius pMUT also fits the values from analytical model on acoustic domain.