Piezoelectric resonators loaded with viscoelastic and nonuniform media

This paper uses a simple, plane bulk acoustic wave model to discuss effects arising from changes occurring at the vibrating surfaces of a piezoelectric resonator, when exposed to coatings having various properties, as well as a variety of interfacial contact behaviors. The effect of air loading on the Q values of the three thickness modes of an SC-cut quartz resonator is computed for various pressures as an example of mode coupling by mechanical boundary conditions.