| 摘要 |
PURPOSE:To reduce the phase difference between surface waves propagating around the center axis and at the end, by locating a small electrode between reed screen electrodes and opposing dummy electrodes. CONSTITUTION:Dummy electrodes 2 are provided opposingly to reed screen electrodes 1. A phase compensation electrodes 5 are provided at the same time a as the forming of the both electrodes among the both electrodes. The surface waves propagate orthogonally lengthwise the reed screen electrodes 1. In this case, the surface waves passing under the reed screen electrodes and the dummy electrodes 2 and those passing through the both electrodes cause a phase shift due to difference of propagation speeds, but the phase shift can almost be avoided in passing under the phase compensating electrodes 5. Since the surface waves passing through any position have equal distance passing under the electrodes, the effect by electrodes is equally received. Thus, singnals almost without distortion due to phase shift can be obtained at the output side. |
