Patent ID: 6833774
Filing Date: 2004-12-21
Classification: H03H

Abstract:
A SAW filter comprising:a piezoelectric substrate of a single crystal LiNbO3 having a SAW propagation surface defined by orientation Euler angles (&lgr;, &mgr;, &thgr;), with angle &lgr; having a value in a range from âˆ’5Â° to 5Â°, angle &mgr; having a value in a range from 75Â° to 85Â°, and angle &thgr; having a value in a range from 85Â° to 95Â°; and at least one first SAW resonator affixed to the propagation surface in at least one parallel arm of the filter and at least one second SAW resonator affixed to the propagation surface in at least one series arm of the filter, wherein electrodes forming each of the at least one first and second resonators have a metalization ratio in a range of 0.3 to 0.9 and a thickness in a range of 8% &Lgr; to 9% &Lgr;, where &Lgr; is an acoustic wavelength of a SAW excited on the piezoelectric substrate, and wherein the metalization ratio for the first resonator in the parallel arm is 1.1 to 1.4 times larger than the metalization ratio for the resonator in the series arm.