Patent ID: 7804221

Claim:
A surface acoustic wave device comprising: an LiNbO 3 substrate having Euler angles of approximately 0°±5°, θ±5°, and 0°±10°; an electrode that is disposed on the LiNbO 3 substrate and that has an IDT electrode mainly made of 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 substantially equal to that of the electrode; and a second silicon oxide film that is disposed 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 is set so as to fall within a range that satisfies the following inequality: −10× D +92.5−100× C ≦θ≦37.5× D 2 −57.75× D +104.075+5710× C 2 −1105.7× C +45.729 D: duty C: thickness of the IDT electrode normalized using a wavelength λ.