Longitudinal leaky surface acoustic waves in periodic systems of metal electrodes on lithium niobate

The LLSAW in lithium niobate on stress-free surface reveals rather high attenuation of the order of one dB per wavelength. Calculated resonant characteristics of a long IDT and dispersion curves of LLSAW propagating in periodic electrode structures show that the attenuation is reduced to values of 0.1-0.5dB per wavelength. The model of propagation of LLSAW in an isotropic solid with periodically corrugated surface is considered. Dispersion curves calculated using this model qualitatively agree with those for YZ-cut of lithium niobate. It is shown that low attenuation of LLSAW in large amplitude periodic structures results from interaction of longitudinal SSBW and their localization near surface.