| 摘要 |
PURPOSE:To reduce the size of a substrate, to suppress the diffraction loss and to improve impedance by dividing at least one inter-digital electrode out of two into plural parts in the surface wave transmitting direction and connecting these parts electrically in series. CONSTITUTION:Input/output side inter-digital elecrodes 21, 22 are formed on a surface wave substrate 20 at a prescribed distance. One electrode 21 is constituted by the 1st and 2nd inter-digital electrodes 23, 24. The electrode 23 is weighted at its cross width so as to be inclined at the right and left positions of an oscillation source 23c setting an envelope to the maximum cross width by shifting and dispersing a zero oscillation source 23d included in the electrode 23 in the length direction of an electrode finger. The electrode 24 is set so that an oscillation source positioned close to the oscillation source 23c is made to zero, and the respective oscillation sources of the electrode 24 can be concentrated on the position maximizing the exitation intensity in the length direction of the electrode finger by shifting and dispersing the zero oscillation source included in the remaining oscillation sources in the length direction of the electrode finger. |
