Surface acoustic wave device

Abstract

A surface acoustic wave device has high power withstanding performance and is able to effectively suppress an undesirable spurious response. The surface acoustic wave device includes an LiNbO3 substrate having Euler angles (0°±5°, θ±5°, 0°±10°), an electrode that is disposed on the LiNbO3 substrate and that has an IDT electrode made mainly from Cu, a first silicon oxide film that is disposed in an area other than an area in which the electrode is disposed to have a thickness equal to that of the electrode, and a second silicon oxide film that is disposed so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrode is less than or equal to about 0.49, and θ of the Euler angles (0°±5°, θ±5°, 0°±10°) is set to fall within a range that satisfies the following inequality: −10×D+92.5−100×C≦θ≦37.5×D2−57.75×D+104.075+5710×C2−1105.7×C+45.729 D: duty C: thickness of the IDT electrode normalized using a wavelength λ.

Dependencies are inferred from the claim text.