This paper presents characterization and initial imaging results of a 32 x 32 element two-dimensional capacitive micromachined ultrasonic transducer array. The devices are fabricated using a wafer bonding process in which both the insulation layer and the membrane are user-deposited silicon nitride. The transducers use a row-column addressing scheme to simplify the fabrication process and beamformer. By adjusting the number of rows and columns that are biased, the effective aperture of the transducer can be adjusted. This is significant because it permits imaging in the near-field of the transducer without the use of a lens. The effect on the transmit beam profile is demonstrated. The transducer has a center frequency of 5.9 MHz and a relative bandwidth of 110%. Images of horizontal and vertical wires are taken to demonstrate image resolution. A three-dimensional image of four pin heads is also demonstrated.
To my supervisor, Prof. Yeow. Thank you for giving me the opportunity to work in AMNDL. Thank you for supporting all the equipment/materials, and facility accesses. I know how expensive they are and without you, I would not have been able to execute my ideas and finish the projects. To my committees, Prof. Huissoon, Prof. Nieva and Prof. Stashuk, Thank you for all the comments and suggestions on my project. Additionally, I would say thank you to Prof. Huissoon. You gave me the to come to study in Waterloo and I will never forget the time I received your email where you asked me to come to Canada. To Prof. Cretu, thank you for agreeing to be the external committee and travelling to Waterloo for my defence. The CMUTs in this thesis were fabricated in G2N and TNFC. I would say thank Richard,
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