Coupling of Love waves with the bulk elastic waves in the substrate

摘要

In an elastically isotropic thin film having a free surface with a weak periodic corrugation, deposited on a semihyphen;infinite substrate of another elastically isotropic material, the interaction between the Love wave guided along the film and the horizontal shear bulk elastic wave propagating in the substrate is investigated for the propagation directions lying in a plane perpendicular to the film and containing the grating vector. The transport equation for the guided Love wave incorporating the effect of the coupling with the bulk elastic wave is deduced. The theory is applied to obtain the characteristics of the output coupler in which the Love wave guided along the film radiates a bulk elastic wave in the substrate as well as those of an input coupler in which a bulk elastic wave incident on the grating region of the film launches the Love wave along the film. Energy conservation principle and the reciprocity between the output and the input couplers are examined.