To increase an output electric signal level by providing a crossing part of an electrode pair of output interdigital electrodes for a waveguide so as to suppress a loss due to spread of a surface acoustic wave to the outside of an output electrode.
The crossing parts of electrode finger pairs 1311, 1312,...,131x of an input electrode 121 and an output electrode 131 are arranged on a projection 102 formed a piezoelectric substrate 101, and output signal bus bars 1321, 1322 are arranged on the piezoelectric substrate 101. The projection 102 formed on the piezoelectric substrate 101 acts like a so-called topograhic waveguide. A surface acoustic wave stimulated by the input electrode 121 at the same plane on the projection 102 is not spread to the outside of the output electrode 131 but propagates the surface of the projection 102 and an output electric signal is extracted by the electrode finger pairs 1311, 1312,..., 131x of the input electrode 121. The level of the output electric signal is nearly equal independently of the distance from the input IDT, then the output electric signal level obtained from the output electrode is improved.
EGARA KOUICHI
EGUCHI TADASHI
HACHISU TAKAHIRO
KOYAMA AKIHIRO
TORISAWA AKIRA
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