| 摘要 |
PROBLEM TO BE SOLVED: To provide a band rejection filter having a narrow rejection bandwidth whose structure is compact in size and simple. SOLUTION: A band rejection filter having a multi layer structure in which a signal conductor of a strip shape is provided among a plurality of dielectric layers 1a to 1h. The signal conductor of the strip shape having an input terminal and an output terminal includes a signal conductor 3 of a main line provided in at least one layer of the plurality of dielectric layers and signal conductors 11, 21 and 31 for a plurality of resonators each having a length of an approximately 1/4 wavelength, whose wide width sides face the signal conductor 3 of the main line through at least one dielectric layer, and which are arranged in approximately parallel and are electromagnetically coupled to the signal conductor 3 of the main line, respectively. One end of the respective signal conductors 11, 21 and 31 for the plurality of resonators is an open end, the other end is electrically connected to the signal conductor of the main line through a first connection conductor to form a coupled line type resonance circuit and the coupled line type resonance circuits are connected in series. COPYRIGHT: (C)2008,JPO&INPIT
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