| 摘要 |
PROBLEM TO BE SOLVED: To make an IDT and a reflector to be securely disposed along a direction of a group velocity of a surface acoustic wave of an in-plane rotational ST-cut crystal plate. SOLUTION: A surface acoustic wave element piece 50 has an IDT 34 on a surface of a crystal plate piece 52, and reflectors 36 disposed at both side of the IDT 34. The crystal plate piece 52 is formed from the in-plane rotational ST-cut crystal plate having a cut angle (0°, 113°to 135°,±(40°to 49°)) when being indicated by the Eulerian angles. The IDT 34 and the reflectors 36 are disposed in a direction inclined by PFA±3°with respect to a direction 40 of a phase velocity of the surface acoustic wave of the crystal plate piece 52. A power flow angle PFA is PFA=0.374(θ°-90°)-10.0°when the cut angle of the crystal plate piece 52 is indicated (ϕ°,θ°,ψ°) by the Eulerian angles. COPYRIGHT: (C)2005,JPO&NCIPI
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