Design and performance analysis of capacitive micromachined ultrasonic transducer (CMUT) array for underwater imaging

In this paper, a Receipt & Transmission CMUT array has been developed for underwater imaging purposes. To guide the array design more intuitively, directivity fuctions of CMUT array are deduced in accordance with its structure feature. According to the simulation results, the optimized CMUT array configuration is selected. Through employing a Si-SOI bonding technique, the CMUT array has been fabricated. Finally, the underwater imaging system design and performance testing are completed. The −6 dB center frequency is centered at 460 kHz and has a relative bandwidth of 130 %. The −3 dB main beam width is about 4°. These values imply that the designed CMUT array has wide bandwidth and fine directivity. Using sector scanning and echo processing, obvious position and image of the obstacles has been reconstructed. This further demonstrates that CMUT array presented in this paper can be of great benefit in underwater detection systems.