Simulation design of a high-frequency piezoelectric micromachined ultrasonic transducer (PMUT) with narrow-pitch array

Purpose Enhancing the high-frequency performance of piezoelectric micro-electro-mechanical ultrasonic transducers (PMUTs), particularly the transmission performance of PMUT arrays, is a key focus in the advancement of MEMS technology. In this paper, a design strategy for a high-frequency ultrasonic transducer array based on aluminum nitride (AlN) is proposed. Design/methodology/approach This paper proposes a design scheme for a high-frequency ultrasonic transducer array based on AlN material. This study established a three-dimensional finite element model of a PMUT and further designed two representative diaphragm structures – circular and hexagonal – as its sensing elements. Using multiphysics finite element simulation, this study focuses on optimizing the diaphragm shape of the PMUT-sensitive element. Concurrently, it proposes a honeycomb-like ultra-narrow equidistant arrangement scheme based on sealed silicon cavity technology and conducts acoustic performance simulations of the PMUT array. Findings By comparing the performance of different diaphragm shapes and array structures in terms of transmit voltage response, reception sensitivity, axial pressure distribution and array acoustic beam patterns, it is concluded that circular diaphragms and PMUT arrays based on equidistant narrow arrays exhibit outstanding acoustic performance. Originality/value This work not only provides valuable guidance for the design, simulation and fabrication of PMUT-sensitive units but also offers novel insights into the application of PMUT arrays in high-frequency scenarios.