Design, fabrication and characterization of a capacitive micromachined ultrasonic probe for medical imaging

In this paper we report the design, fabrication process, and characterization of a 64-elements capacitive micromachined ultrasonic transducer (cMUT), 3 MHz cen- ter frequency, 100% fractional bandwidth. Using this trans- ducer, we developed a linear probe for application in medi- cal echographic imaging. The probe was fully characterized and tested with a commercial echographic scanner to ob- tain first images from phantoms and in vivo human body. The results, which quickly follow similar results obtained by other researchers, clearly show the great potentiality of this new emerging technology. The cMUT probe works better than the standard piezoelectric probe as far as the axial res- olution is concerned, but it suffers from low sensitivity. At present this can be a limit, especially for in depth operation. But we are strongly confident that significant improvements can be obtained in the very near future to overcome this limitation, with a better transducer design, the use of an acoustic lens, and using well matched, front-end electronics between the transducer and the echographic system.