Design of an ultrasonic sensor to emulate bat bio-sonars

Curved transducers, based on piezo-polymer technology, were used to generate ultrasonic waves in air. They are capable of resonating in a controlled manner by simply changing the bending radius, and have already been employed to synthesize elementary wave forms of bat pulses. Much more complex echo-location systems may be emulated by using similar ultrasonic sensors. In particular, curved piezo-polymer transducers may be used to control frequency, resolution, and penetration depth, according to the features of the target. In this paper we present the design of a prototype sonar, based on PVDF, which includes both an electronic block, to drive the transducer at the desired frequency, and a mechanical block, which includes a dc motor to impose the desired curvature on the transducer.