Doubly resonant cymbal-type transducers

A doubly resonant cymbal-type transducer has been developed by capping a poled piezoceramic disk asymmetrically. It is intended for use in the frequency range between 10 and 50 kHz. The two resonance frequencies can be easily manipulated by selecting appropriate cap materials and/or geometry. The prominent feature of this device is the ability to obtain two resonances at desired frequencies without the need for electrical tuning. In addition, proper placement of the resonance frequencies may also allow for the broadening of the operational bandwidth as well as the generation of difference frequencies.