| 摘要 |
A multiple bandpass filter is disclosed having a common input intercoupling a plurality of parallel single bandpass filters which are further intercoupled to provide a composite signal at a common output. The multiple bandpass filter of the present invention is appropriate for application to ceramic filters. In a preferred embodiment, the multiple bandpass filter of the present invention has a common input, parallel distributed resonator single bandpass filters, and a common output, all integral to the same ceramic structure. The multiple bandpass filter comprises a ceramic block having a plurality of rows of holes extending from the top of the bottom of the block and a slot extending from the top to the bottom of the block, separating the rows. The block and interior of the holes and slot are substantially covered with conductive material. An area near one end of each of the holes is bare ceramic. The individual rows of holes are the individual single bandpass filters, each hole being a resonator element of the filter. The filters are typically of the combline or intergidital variety. The slot electromagnetically isolates the filters from one another. In a preferred embodiment, the respective ends of the parallel single bandpass filters are each coupled and matched with a common transformer being an additional conductive material covered hole extending from the top to the bottom of the ceramic block.
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