| 摘要 |
A folded high frequency resonant cavity filter 30 includes a filter housing 32 that contains a half-wave resonator rod 36, 64 and a plurality of evanescent mode resonator rods 34, 34'. The half wave resonator rod 36, 64 and plurality of evanescent mode resonator rods 34, 34' are mounted to the filter housing 32 such that they all lie alo ng a single plane. The filter housing 32 has an inner wall 42 that physically isolates two grou ps of evanescent mode resonator rods 34, 34' from each other. An aperture 40 is formed in the inner housing wall 42 between two physically opposing evanescent mode resonator rods 34' t o allow a capacitive cross-coupling to occur between the two evanescent mode resonator rods 34'. The capacitive cross-coupling is fine tuned by a tuning rod 44 that is positione d through the inner wall 42 and within the aperture 40. The half-wave resonator rod 36, 64 can b e either a shunt half-wave resonator rod 36 or a series half-wave resonator rod 64, whereby the shunt half-wave resonator rod 36 is fine tuned by a tuning disc 46 and the series half-wave resonator rod 64 is fine tuned by a pair of tuning rods 68. Input and output ports 48 are supplied with coupling loops 49 to allow input and output coupling, respectively, with the filter 30.
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