| 摘要 |
PURPOSE:To increase the performance of the multi-strip coupler, by taking the repetitive period of the arrangement of metal pieces as a half the read screen shaped electrode period, and providing the flat shape electrode corresponding to the reed screen type electrode. CONSTITUTION:On the piezoelectric substrate 1, lambda or less in thickness (wave length of acoustic wave on the substrate), the arrangement 2 of metal pieces, acoustic generating source 3, reception means 4 and reed screen shaped electrode 5 are provided. Further, the repetitive period of the arrangement 2 is set to 1/2lambda to obtain excellent reflection performance and to a half the electrode period of the reed screen shaped electrode 5. Further, at the back of the substrate 1, the flat shape electrodes 6a, 6b are respectively provided corresponding to the arrangement 2 and the electrode 5. Thus, the effect of the change in the rhm wave velocity due to the electrode 6a can be avoided by providing the flat shape electrode with the electrode 5 also. Thus, the performance of reflection with the coupler can be increased. |
