“…Thai is, the resonance frequency is influenced by other mechanical compliances in the system such as the compliance of the piezoelectric ceramic driver, Cd. Woollett [41 identified the relationship between the cavity compliance, C', and the driver compliance, Cd, as an important design parameter and defined it as C, C- (2) Cd +C" It can be shown that for a given design, the output power is proportional to the factor (I -c2) while the viscous loss in the cavity is inversely proportional to (I -cc). Therefore, if the compliance of the driver becomes large in relation to the compliance of the cavity, the output power will decrease and the viscous loss in the cavity will increase.…”