| 摘要 |
The invention is to realize a surface acoustic wave device that attains a wide band and a small size, and lowers a loss by utilizing the natural single-phase unidirectional transducer characteristics.The surface acoustic wave device comprises a piezoelectric substrate (1) and a pair of interdigitated electrodes (2) provided on one main surface of the piezoelectric substrate 1. As the material of the piezoelectric substrate (1), a single crystal is used that belongs to the point group 32, has the Ca3Ga2Ge4O14 type crystalline structure, comprises La, Ta, Ga and O as main components, and is represented by a chemical formula La3Ta0.5Ga5.5O14. When the cut angle of the substrate (1) and the propagation direction are represented by Eulerian angles (phi, theta, psi), phi, theta and psi are in a first region where phi is from -5° to 5°, theta is from 135° to 155°, and psi is from 15° to 40°, or in a second region where phi is from 10° to 20°, theta is from 140° to 157°, and psi is from 30° to 60°.
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