Edge reflection type surface acoustic wave device

摘要

An edge reflection type surface acoustic wave device (1) includes a surface acoustic wave substrate (2) having an opposing pair of edges (2b,2c) and at least one interdigital transducer (3) located on the surface acoustic wave substrate. A Shear Horizontal type surface acoustic wave is generated by the interdigital transducer (3) and reflected between the opposing pair of edges (2b,2c). The interdigital transducer is divided into a plurality of sub-IDT portions along a surface acoustic wave-propagating direction. Electrode fingers (6a,8a) of the interdigital transducer which are closest to each other between adjacent sub-IDT portions are at the same potential so as not to be excited between the adjacent sub-IDT portions. In addition, when it is assumed that the widths of the outermost electrode fingers in the surface acoustic wave-propagating direction of the interdigital transducer are equal to the widths of the remaining electrode fingers before cutting of the substrate, the edges are arranged such that the edges (2b,2c) are cut at a location inside of the center of the outermost electrode fingers in the surface acoustic wave-propagating direction such that a distance between the opposite edges of the substrate is not an integral multiple of lambda 0/2.