WAVEGUIDE OF SURFACE ACOUSTIC WAVE

摘要

PURPOSE:To make possible the conversion of the three beams; parallel beams, divergent beam and convergent beam to each other by changing the thickness of a thin waveguide film of surface acoustic wave in the direction perpendicular to the propagating direction of a surface wave. CONSTITUTION:The dielectric film as the waveguide 1 of the surface acoustic wave to be provided on a substrate 2 is made larger in the film thickness at the center thereof than the film thickness at both ends. Then the phase speed or the surface wave at the center is lower than the speed at both ends and the direction where the surface wave propagates is deflected toward the direction where the phase speed is lower. The parallel beams 3 made incident from an end face X-X' are therefore deflected like broken lines 6 while the beams are propagated in the waveguide 1. The parallel beams are converted to the convergent beam 4 in the stage when said beams are emitted therefrom. The divergent beam is obtd. if the thickness at the center is decreased. The conversion of the shape of the surface acoustic wave to each other is thus made possible.