| 摘要 |
PURPOSE:To decrease spurious radiation by leading a terminal electrode from a surrounding electrode and connecting other surrounding electrode arranged at the outside of a surrounding electrode of common potential to other comb-tooth electrode of an interdigital transducer (IDT) electrode and one comb-tooth electrode of other IDT electrode. CONSTITUTION:Other comb-tooth electrode 12b of one input IDT electrode 12 and one comb-tooth electrode 13a of other input IDT electrode 13 are connected by other surrounding electrode 21 arranged at the outside of the surrounding electrode of common potential. Since the IDT electrodes 12, 13 at both sides are connected by the channel form surrounding electrode 20 of common potential, the surrounding path is not crossed and since the surrounding electrode 20 of common potential is arranged between the input IDT electrodes 12, 13 and the output IDT electrode 11, the direct wave is suppressed effectively and the cause to a spurious radiation specific to a surface wave filter is solved at the same time. |
