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Characterization and operation of different cMUT membranes in air

Capacitive micromachined ultrasonic transducers (cMUT) have emerged as an alternative technology to piezoelectric transducers. The paper presents characterization measurements of several membranes with different geometries and materials, aimed at an optimization of the membrane configuration for different applications. In parallel, suitable testing and readout electronics have been developed. We report electro-mechanical measurements and in-air uncoupled testing of devices fabricated in a dedicated process, appropriate for short-range ultrasound transmission.