Design, Fabrication and Characterization of a Capacitive Micromachined Ultrasonic Probe for Medical Imaging

Abstract--In this paper we report the design, fabrication
process, and characterization of a 64-elements capacitive
micromachined ultrasonic transducer (cMUT), 3 MHz center
frequency, 100% fractional bandwidth. Using this transducer,
we developed a linear probe for application in medical
echographic imaging. The probe was fully characterized
and tested with a commercial echographic scanner to obtain
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 resolution
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.