Characteristics of Lamb waves in piezoelectric ceramics

The concept of effective permittivity of a plate is used to calculate the Lamb wave eigenfrequencies. Phase and group velocities as well as the electromechanical coupling coefficient for various electrical boundary conditions are calculated as a function of thickness to wavelength ratio. The theoretical analysis is experimentally verified by measuring the resonant frequencies of Lamb wave delay lines fabricated on Pz27 and Pz34 commercial ceramics.