| 摘要 |
PROBLEM TO BE SOLVED: To provide a polar band-reject filter which has pass characteristics with both flatness in attenuation characteristics in the bottom of an inhibition zone and sharpness in rising at both sides of the bottom of the inhibition zone, and is capable of attenuating the signal of a desired channel with no problem, without attenuating the signal of an adjacent channel excessively. SOLUTION: The polar band-reject filter comprises a first resonator 16 for forming a first attenuation pole f<SB>L</SB>in a configuration being branched from a first branch point on a signal transmission line 83 to a ground side, and resonantly coupling in parallel a dielectric resonator RES1 and capacitors C3, C4; and a second resonator 17 for forming a second attenuation pole in a configuration branched from a second branch point different from the first branch point to the ground side, and resonantly coupling in parallel a dielectric resonator RES2 and capacitors C5, C6. Further, a coupling circuit 60 is provided which includes a coupling circuit side LC parallel resonator 10R for attenuating a ripple generated between the first attenuation pole and the second attenuation pole in a cut-off zone, in a form coupling the first resonator 16 and the second resonator 17 on the signal transmission line 83. COPYRIGHT: (C)2008,JPO&INPIT
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