SURFACE ACOUSTIC WAVE DEVICE

摘要

PURPOSE:To contrive the reduction of a periodical spurious radiation by folding a part of a common electrode parted from other comb-line electrode in a direction decreasing gradually the length of a non-cross part of electrode fingers and providing a tilt ridge with an angle in the propagation direction of a surface acoustic wave to the folded part. CONSTITUTION:The surface acoustic wave device is constituted by providing an apotized type comb-line electrode 21 of tilt electrode structure to a substrate 20 made of a prescribed piezoelectric substance. The electrode 21 has plural electrode fingers 21a common electrodes 21b, 22 connected in common to the electrode fingers. Then the part of the common electrode 22 parted from the normal comb-line electrode 23 in the electrode 21 is folded in a direction decreasing gradually the length of the non-cross part of the electrode finger 21a from the position of the acoustic center A to form a folded part 22A. The folded part 22A has a tilt ridge tilted at a prescribed angle in the propagation direction (direction of arrow) of a surface acoustic wave being a main reply surface wave to the outer ridge.