Frequency characteristics of an interdigital transducer for Lamb wave excitation

摘要

The frequency characteristics of the surface displacements of the Lamb waves excited by interdigital transducers on unpolarized piezoelectric ceramic plates have been analyzed by using the same method as Tseng's analysis of Rayleigh wave excitation. This analysis has lead to the conclusion that the transducer operates most effectively when the wavelength of the Lamb wave is equal to the half‐period of the electrode. The dispersive characteristics of the zeroth modes in a comparatively thick specimen are also shown. Our discussion dwells on the frequency dependence of the surface displacement on the total number of the electrode fingers in a transducer and the electrode configurations.