COUPLED-MODE ANALYSIS OF LOVE WAVES IN A FILTER FILM WITH PERIODICALLY CORRUGATED SURFACES

Mode coupling of Love waves in an orthotropic thin film having periodi cally corrugated surfaces over an isotropic elastic half space is cons idered. Six modes are coupled by both surfaces by means of three simul taneous resonant conditions. On the basis of the weakness of the corru gations, the method of multiple scales is used to derive the coupled-m ode equations. These equations together with relevant boundary conditi ons form a two-point boundary-value problem, which is solved numerical ly. The filter frequency response of a corrugated film designed as a s top-band filter is calculated. Enhanced filter characteristics are ach ieved when tapered corrugations are imposed. A narrow pass-band filter is also designed. Its high quality factor presents the fascinating fe atures that might be realized by including the periodic corrugations i n the design of SAW devices.