| 摘要 |
PROBLEM TO BE SOLVED: To provide the surface acoustic wave element that has an excellent frequency characteristic by eliminating a leakage wave from an IDT and is much more miniaturized. SOLUTION: An input IDT 6a, an output IDT 6b and a bonding pad 7 are respectively placed on a piezoelectric substrate 5 of the surface acoustic wave element. One or two or over of recessed parts 10 (recessed holes 8 or recessed grooves 9) whose depth is shallower than a wavelengthλof a surface acoustic wave are placed on a region between the IDT 6 and an end face of the major side in a propagation direction of the surface acoustic wave stimulated by the IDT 6. In the case of the recessed grooves 9, it is desired that the inner circumferential face of the grooves 9 toward the IDT 6 is placed at an tilt angle other than the right angle in a progress direction of the surface acoustic wave. The effect of improving the frequency characteristic is furthermore enhanced by selecting the shape of the recessed part and sizes of the element such as a width of the bottom face so that reflected waves by the recessed parts 10 are interfered and cancelled together.
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