| 摘要 |
There is provided a transversal type elastic surface-wave filter having preferable filter characteristic not causing ripple by an unnecessary wave or ripple by a re-excitation wave even when the filter is made in a small size. The transversal type elastic surface-wave filter includes an input side IDT electrode (3), an output side IDT electrode (4), and a shield electrode (5) formed on a surface-wave substrate (2). In the elastic surface-wave filter (1), the distance X between the excitation point A nearest to the shield electrode (5) of the input side IDT electrode (3) and the middle point B between the end of the input side IDT electrode (3) at the side of the shield electrode (5) and the end of the shield electrode (5) at the side of the input side IDT electrode is in a range from 0.8lambda to 0.975lambda wherein lambda represents a wavelength of the surface wave. ® KIPO & WIPO 2007
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