between the resonance and antiresonance frequencies is, thelarger the electromechanical coupling factor.The energy loss during the operation of an electromechanicalsystem is of great concern in device fabrication, as the loss bringsabout reliability issues due to self-heating of the material.125Generally, both dielectric and mechanical dissipation must beconsidered. The former is important when the device operatesat off-resonance frequencies, while the latter is critical when thematerial is driven in resonance modes. The mechanical qual-ity factor is inversely proportional to the difference betweenantiresonance and resonance frequencies. Hence, it is commonlyconsidered that the enhancement of this property is achieved atthe expense of the electromechanical coupling factor. Quartzthus exhibits a coupling coefficient of about 0.1 and Qmup to106while donor doped PZT exhibits a coupling coefficient of0.5–0.7 and a Qmon the order of 102.1265.2. Figures