Development of a 6×6 Element Air-Coupled Multiple Moving Membrane Capacitive Micromachined Ultrasonic Transducer Array, M3-CMUT, for High Resolution Detection Applications

A 2-D multiple moving membrane capacitive micromachined ultrasonic transducer (M3-CMUT) array has been developed for air-coupled detection purposes in the megahertz frequency range. The transducer includes an array of 6×6 M3-CMUT elements. This transducer benefits from a novel configuration where a stack of two vibrating membranes suspended over a fixed grounded electrode are involved in the signal transmission and detection. Using this configuration, the amplitude of membrane vibration is increased and that enhances the transducer power output and sensitivity. Electrical and acoustic characterization of this transducer array is presented in this paper.