| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave device, using a lithium tetraborate single crystal substrate for reducing characteristic deterioration due to the influence of the diffraction of a surface acoustic wave, and realizing the miniaturization of the device. SOLUTION: In a surface acoustic wave filter having a wide band pass band using the lithium tetraborate single crystal substrate 10, the values of Euler angles (λ,μ,θ) for deciding the substrate surface and the propagating direction of surface acoustic waves to the lithium tetraborate single crystal are set as (λ=45°) and (μ=90°) and (75°≤θ<80°or 100°<θ≤105°). Therefore, it is possible to make the value of an anisotropic constantγclose to -1, and to reduce the spread of the waves due to diffraction even when valid opening length is short. Thus, it is possible to reduce the deterioration of filter characteristics, and to obtain the filter characteristics as designed, and to realize the miniaturization of the filter at the same time. COPYRIGHT: (C)2004,JPO
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