Suppression of attenuation of leaky surface acoustic waves by loading dielectric thin-film

The attenuation characteristics of leaky surface acoustic waves (LSAWs) on rotated Y-cut X-propagating LiNbO/sub 3/ loaded with dielectric thin-films such as Ta/sub 2/O/sub 5/ and SiO/sub 2/ were investigated theoretically and experimentally. The calculated attenuation as a function of the rotation angle from the Y-axis showed that the rotation angle giving the zero-attenuation shifts as the film-thickness is increased. This means that, within a certain range of the rotation angle, the attenuation can be suppressed by choosing the kind of film and its thickness. In fact, for the two cases of the free surface of 64/spl deg/ Y-X LiNbO/sub 3/ with RF-sputtered Ta/sub 2/O/sub 5/ film and the metallized surface of 41/spl deg/ Y-X LiNbO/sub 3/ with RF-sputtered SiO/sub 2/ film, the measured propagation losses decreased to 1/4/spl sim/1/2 in comparison to the sample without a film.