Patent ID: 8436696
Filing Date: 2013-05-07
Classification: H03H

Abstract:
1. A surface acoustic wave device, comprising: a piezoelectric substrate; a surface acoustic wave element formed on the piezoelectric substrate and comprising first to fifth IDT electrodes aligned, in a propagation direction of a surface acoustic wave propagating on the piezoelectric substrate, and each comprising, along the propagation direction, a plurality of electrode fingers long in a direction perpendicular to the propagation direction, and reflector electrodes arranged on both sides of the propagation direction of the first to fifth IDT electrodes and each comprising a plurality of electrode fingers long in the direction perpendicular to the propagation direction; and an unbalanced signal terminal and balanced signal terminals connected to the surface acoustic wave element, wherein the first to fifth IDT electrodes further comprise a first to fourth electrode finger narrow pitch portions, the first to fourth electrode finger narrow pitch portions each comprises a gap between adjoining two IDT electrodes and at least two adjoining electrode fingers of each of the adjoining two IDT electrodes located closer to the gap, and are formed symmetrically around the third IDT electrode located at the center, and a pitch of the first electrode finger narrow pitch portion is narrower than a pitch of the second electrode finger narrow pitch portion and a pitch of the fourth electrode finger narrow pitch portion is narrower than a pitch of the third electrode finger narrow pitch portion.