Acoustic Simulation and Characterization of Capacitive Micromachined Ultrasonic Transducers

Ultrasonic transducers are used in many fi elds of daily life, e.g. as parking aids or medical devices. To enable their usage also for mass applications small and low-cost transducers with high performance are required. Capacitive, micromachined ultrasonic transducers (CMUT) offer the potential, for instance, to integrate compact ultrasonic sensor systems into mobile phones or as disposable transducer for diverse medical applications. This work is aimed at providing fundamentals for the future commercialization of CMUTs. It introduces novel methods for the acoustic simulation and characterization of CMUTs, which are still critical steps in the product development process. They allow an easy CMUT cell for given application requirements. Based on a novel electromechanical model for CMUT elements, the device properties can be determined by impedance measurement already. Finally, an end-of-line test based on the electrical impedance of CMUTs demonstrates their potential for effi cient mass production.