P3R-3 Design and Characterization of Air Coupled Ultrasonic Transducers Based on MUMPs

This paper deals with the design and characterization of several capacitive micromachined ultrasonic transducer (cMUT) cells for the future design of an air-coupled transducer for non destructive testing (NDT). Each design was manufactured using the multi-user MEMS process (MUMPs). Special boundary conditions were used to obtain high efficiency: two opposite sides of the 150 mum square shaped membranes are free while the other sides are anchored to a fixed layer of the process. Using these designs a large displacement of the membrane and a higher surface contact is obtained in spite of their mechanical losses