| 摘要 |
PURPOSE:To elevate a characteristic of a surface acousitic wave device for a channel selecting device of a TV receiver, to decrease the number of processes, and to reduce a cost of the device, by constituting said device to that it is operated by a VHF low band, a VHF High band and a UHF band. CONSTITUTION:The first-the third electrodes (1-2-1, 1-2-2), (2-2-1, 2-2-2) of the low band side of a VHF High band are constituted of a comb shaped electrode, a part of which is at equal intervals, and the first-the third electrodes (1-3-1, 3-3-2), (2-3-1, 2-3-2) of an electrode group of the low band side of a UHF band are constituted of a comb shaped electrode, a part of which is at equal intervals. Frequency which becomes a boundary of the low band side and the high band side in the UHF band is smaller than about 1.28 times of center frequency of a stopping band by a periodic structure (3-3), and a periodic structure (3-1) and (3-2), and a distribution constant line 4 are prepared by the same process. Also, an electrode group in the VHF low band, an electrode group in the VHF High band, an electrode group in the UFH band, and the periodic structure are prepared by the same process. |
