Patent ID: 6946932
Filing Date: 2005-09-20
Classification: H03H

Abstract:
1. A surface acoustic wave resonator, comprising: a piezoelectric plate; an interdigital transducer to excite a surface acoustic wave in a propagation direction x on the piezoelectric plate; and a pair of reflectors arranged on both sides of the interdigital transducer in a propagation direction; the interdigital transducer being divided into three regions and including electrode fingers, the electrode fingers of the interdigital transducer of each region being formed at a fixed pitch which varies within 2%, the surface acoustic wave resonator possessing a single peak response, a form in which a vibration displacement envelope amplitude in the interdigital transducer region is normalized by its maximum value being a form which takes a maximum value 1 at a center position of the interdigital transducer region, which smoothly takes a value in a range of 0.33 to 0.53 at a position of ¼ of the total length of the interdigital transducer region from both ends thereof, and which smoothly takes a value in a range of 0.048 to 0.177 at positions at both ends of the interdigital transducer region.