Jf. Tressler et Re. Newnham, DOUBLY RESONANT CYMBAL-TYPE TRANSDUCERS, IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 44(5), 1997, pp. 1175-1177
A doubly resonant cymbal-type transducer has been developed by capping
a poled piezoceramic disk asymmetrically. It is intended for use in t
he frequency range between 10 and 50 kHz. The two resonance frequencie
s can be easily manipulated by selecting appropriate cap materials and
/or geometry. The prominent feature of this device is the ability to o
btain two resonances at desired frequencies without the need for elect
rical tuning. In addition, proper placement of the resonance frequenci
es may also allow for the broadening of the operational bandwidth as w
ell as the generation of difference frequencies.