| 摘要 |
PURPOSE:To reduce the influence of diffration by suppressing electromagnetic induction by dividng a multistrip coupler into two, by putting them close to an input and an output transducer espectively, and by providing a shield electrode between the two divided parts. CONSTITUTION:On a piezoelectric substrate 10 where an elastic surface wave propagates, an input transducer 1 which transduces an electric signal into the elastic surface wave and an output transducer 2 which transduces the elastic surface wave into the electric signal are provided at an interval. Then, the input and output transducers are both weighted by apodization and between the both, multistrip couplers 3 and 3' having many stripped conductors periodically are divided into two and arranged close to the transducers 1 and 2. Between the separated multistrip couplers, a sheild electrode grounded at one terminal is provided. |
