| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter capable of suppressing even supurious radiation caused by a quartic mode while suppressing supurious radiation caused by a tertiary mode. SOLUTION: The filter is composed by connecting first/second cascade-connected DMS resonators A, B with each other in parallel. IDT electrodes 2(a), 3(a) are weighted by a thinning-out method in the first cascade-connected DMS resonator A. IDT electrodes 2(b), 3(b) are weighted by the thinning-out method in the second cascade-connected DMS resonator B. The first/second cascade-connected DMS resonators A, B are in a reversed phase relationship. A frequency of a secondary mode is coincident with that of a primary mode of the first cascade-connected DMS resonator A. A frequency of the quartic mode is coincident with that of the quartic mode of the first cascade-connected DMS resonator A. COPYRIGHT: (C)2007,JPO&INPIT
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