| Abstract: | Combs are distributed ultrasonic transducers for the generation of Rayleigh waves in solids. Synchronously excited by subsequent comb teeth, the surface wave grows along its propagation path under the comb. Although sliding contact between the comb and a solid sample is frequently assumed, the mechanical coupling is not weak. This modifies the surface wave propagation conditions to such an extent that the Rayleigh wave no longer exists at the comb–sample interface. Instead, an interface mode propagates, collecting power from each subsequent comb tooth and delivering it to the comb edge to be eventually transformed into a Rayleigh wave outside the comb. Generation efficiency is evaluated for the optimized angle of incidence of the longitudinal wave onto the comb–sample interface. |
