On the performance characterization of ultrasonic air transducers with radiating membranes

An ultrasonic air transducer used for sensing essentially requires an efficient transduction into the surrounding medium. A transducer consisting of a metal membrane coupled with a resonating piezoelectric disk, the latter being driven in its radial mode of vibrations, has been found to be significantly applicable in this aspect. The present study reports the performance characterization at resonance and at higher frequencies of two such transducers with different dimensions of the housings. Vibrational amplitude characteristics are studied employing phase-locked laser interferometry technique that presents sufficiently high displacement amplitude of the membrane at resonance. A consequent high-acoustic pressure field is also obtained. The design aspects for such ultrasonic air transducers with efficient transduction capability and adjustable bandwidth are discussed.