Patent ID: 8723394
Filing Date: 2014-05-13
Classification: H03H

Abstract:
1. A surface acoustic wave device comprising: a piezoelectric substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|≠90°×n (where n=0, 1, 2, 3)); and an IDT which has a plurality of electrode fingers on the principal surface of the piezoelectric substrate and excites a Rayleigh wave in a stopband upper end mode, wherein inter-electrode-finger grooves are recessed in the surface of the piezoelectric substrate between adjacent electrode fingers of the IDT, the wavelength λ of the Rayleigh wave and the depth G of the inter-electrode-finger grooves satisfy the relationship 0.01λ≦G≦0.07λ, the line occupancy η of the IDT and the depth G of the inter-electrode-finger grooves satisfy the following relationships, and the thickness H of the electrode fingers and the line occupancy η of the IDT satisfy any one of the following relationships: (1) 0.010λ≦H≦0.015λ, and 0.575≦η≦0.741 (2) 0.015λ≦H≦0.020λ and 0.605≦η≦0.744 (3) 0.020λ≦H≦0.025λ and 0.605≦η≦0.745 (4) 0.025λ≦H≦0.030λ and 0.575≦η≦0.745.