| 摘要 |
PURPOSE:To obtain a strip line filter with small size and large Qo by providing an active element subjected to capacitive coupling to the open end of a lambda/4 strip resonator and representing a negative resistance at the resonance state of the lambda/4 strip resonator. CONSTITUTION:One terminal of the lambda/4 strip resonator 14 is coupled with a main strip line 14 and an active element 18 is coupled with the other terminal of the lambda/4 strip resonator 16 via a gap capacitance comprising gaps 22a, 22b and a phase adjusting line 20. The active element 18 is not operated at the pass band of the strip line filter 10, that is, at the non-resonance region of the corresponding lambda/4 strip resonator 16 but operated at the attenuation region of the strip line filter 10, that is, at the resonance region and shows a negative resistance. Thus, the apparent resistance of the lambda/4 strip resonator is decreased, the Qo is increased apparently and the Qo of the strip line filter is also increased.
|
