Abstract:

Microfabricated ultrasonic transducers (MUTs) are generating interest as a novel alternative to piezoelectric transducers in many applications. This paper introduces the latest results, both experimental and theoretical, pertaining to the transducers the authors invented. Significant experimental results include air-coupled aluminum through transmission at 2.3 MHz with a system of 110-dB dynamic range, as well as fluid immersion transmission experiments with a dynamic range of at least 100 dB. Air-coupled transmission scans of defects in Plexiglas are demonstrated. Improvements to the authors' fabrication process are highlighted and the paper concludes with a discussion of the energy dissipation mechanisms of the transducer. The main dissipative mechanism is, of course, radiation, but the effects of structure leakage, viscous damping, and thermal flow are introduced into the authors' model. [Work supported by the U.S. Office of Naval Research and by a fellowship from NUS.]