Design of capacitive micromachined ultrasonic transducer for underwater acoustic imaging

Abstract

We introduce Capacitive Micromachined Ultrasonic Transducer (CMUT) for underwater acoustic imaging in order to obtain the high resolution images. CMUT is used because of its several advantages like higher performance, low motional impedance and high quality factor, high bandwidth, less losses. The CMUT consists of a membrane. When AC voltage superimposed with DC voltage is applied across metalized membrane and substrate, ultrasonic waves are produced. The membrane is attracted towards the bulk by the electrostatic force and induced stress within the membrane resists the attraction. If the biased membrane is exposed to ultrasound, a current is generated due to the capacitance change under constant bias voltage. The amplitude of this current is a function of the frequency of the incident wave, the bias voltage, and the capacitance of the device. In this report comparative study of CMUT has been done. Objectives have been drawn from the observations and gaps. Simulation results have been achieved using COMSOL multiphysics.