Patent ID: 7915784

Claim:
A surface acoustic wave resonator comprising: a rotated Y-cut quartz substrate with a cut angle θ of about −53° to about −52°; an IDT electrode provided on a main surface of the quartz substrate, the IDT electrode being made of aluminum or an alloy primarily including aluminum; and a SiO 2 film arranged to cover the main surface of the quartz substrate and the IDT electrode; wherein a propagation direction of surface acoustic waves is within a range of about 90°±5° with respect to the X axis; and a thickness of the IDT electrode is in a range of about 6.0% to about 6.5% of λ, where λ is the wavelength of surface acoustic waves propagating in the quartz substrate, and a duty ratio of the IDT electrode is in the range of about 0.62 to about 0.66.