Design of dual-frequency piezoelectric micromachined ultrasonic transducers

Abstract

A piezoelectric micromachined ultrasonic transducer (pMUT) operating at dual-frequencies (3.75 MHz and 18 MHz) was designed to achieve an ultrasound-on-a-chip solution for next-generation biomedical applications. Unlike transducers using two or more single-frequency ultrasonic resonators to generate dual-frequency ultrasound, every element of dual-frequency pMUTs exhibits dual-resonant response simultaneously. Electrode configurations for the dual-frequency pMUT were optimized using finite element analysis (FEA). Simulations for dual-actuations with both inner and outer ring electrodes showed that the two resonant modes are superimposed without significant vibrational crosstalk, and result in high-quality dual-frequency acoustic radiation in water.