| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small and wideband surface acoustic wave device. SOLUTION: The surface acoustic wave device comprises a piezoelectric substrate 1, and a pair of interdigital electrodes 2 provided on one major surface of the piezoelectric substrate 1. A single crystal belonging to a point group 32, having a Ca3 Ga2 Ge4 O14 type crystal structure, principally comprising Ca, Nb, Ga, Si and O, and represented by the chemical formula Ca3 NbGa3 Si2 O14 is used as the material of the piezoelectric substrate 1. When the cutting angle and the propagating direction of the substrate 1 are selected appropriately, a substrate 1, having a large electromechanical coupling coefficient effective for widening the pass band and a low SAW speed effective for reducing the size of the surface acoustic device, can be realized.
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