FEM-Assisted Analytical Investigation of Stress Gradient Effects on Focalization in ALN-Based Pmut Devices

The simulation of large arrays of piezoelectric micromachined ultrasonic transducers (PMUTs) presents a significant challenge due to the complex coupling effects and the high computational cost associated with Finite Element Modelling (FEM). Traditional FEM simulations become impractical for large-scale transducer arrays, necessitating alternative approaches. In this paper, we propose a hybrid simulation technique that combines FEM with a lumped element model, combining the advantages of both methods to reduce computational complexity while maintaining accuracy. Specifically, we focus on accounting for the residual stress gradient in Aluminium Nitride (AIN) within the PMUT array. Our technique enables the analysis of stress-induced effects on the focalization of pressure in large PMUT matrices, offering insights into optimizing transducer performance under practical conditions.