Patent ID: 6531937
Filing Date: 2003-03-11
Classification: H03H

Abstract:
An edge reflection type surface acoustic wave filter comprising:a piezoelectric substrate having two opposing edges; and at least one interdigital transducer defined by split electrodes of paired electrode fingers and provided on the piezoelectric substrate such that an SH-type surface acoustic wave is excited on the piezoelectric substrate and is reflected between the two opposing edges; wherein each of the two opposing edges is located at a distance of at least about &lgr;/2âˆ’5&lgr;/128 or more from a center of the paired equipotential respective outermost portions, in the surface acoustic wave propagation direction, of the interdigital transducer and less than about &lgr;/2 from the center of the paired equipotential electrode fingers, where &lgr; is a wavelength of the SH-type surface acoustic wave excited on the piezoelectric substrate; and every electrode finger of said at least one interdigital transducer has an equal width.