| 摘要 |
A surface acoustic wave device is provided. The surface acoustic wave device includes a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle ¸ set to a range of -64.0° < ¸ < -49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90° ± 5° with respect to an X crystalline axis, wherein, when a wavelength of an excited surface acoustic wave is denoted by », an electrode film thickness H/» normalized with wavelength of the IDT is set to a range of 0.04 < H/» < 0.12, and wherein, when a line occupancy rate mr of electrode fingers constituting the IDT is defined to be electrode finger width/(electrode finger width + electrode finger spacing), the line occupancy rate mr is set to a range of 0.53 ‰ mr ‰ 0.65.
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