Electrostatic airborne ultrasonic transducers: Modeling and characterization

An a priori theoretical model for electrostatic airborne ultrasonic transducers has been developed. The historical development of transducer modeling is briefly reviewed. This paper applies the plate-on-air-spring model to establish a mathematical formulation for the transducer behavior in terms of the characterized impedance parameters. It is clarified that such an electrostatic transducer is a capacitive-type device and obeys the reciprocity principle in the same way as a piezoelectric device. The accurate prediction of multiple resonant frequencies and transmitting responses for a typical V-grooved backplate transducer serve to substantiate the theoretical model.