Patent ID: 9590285
Date: 2017-03-07
CPC Classifications: H01P,H03J

Claim:
1. A bandpass frequency adjusting method to be used in a bandpass filter, the bandpass filter comprising: a filter casing defining a rectangular waveguide having a narrow plane and a broad plane that is wider than the narrow plane; a metal plate having a ladder shape and being arranged in a sandwiched manner inside the filter casing at a center of the broad plane so as to be parallel to the narrow plane; a dielectric plate positioned in a vicinity of the metal plate in the rectangular waveguide; and a support rod extending in parallel to a longitudinal direction of the rectangular waveguide, the support rod being rotatably supported on the filter casing and configured to support the dielectric plate so that the dielectric plate extends in the longitudinal direction of the rectangular waveguide; a first gear fixed at a tip of the support rod; a second gear meshing with the first gear, the second gear having a smaller number of teeth than the first gear, a spring for locking rotation, which is provided at a position of engagement with the second gear; and a screw provided above the spring, wherein the bandpass frequency adjusting method comprises rotating the first gear along with rotation of the second gear to rotate the dielectric plate, to thereby adjust the bandpass frequency, and when the screw is fastened, fixing movement of the spring by the screw in a state in which a tip of the spring engages with the second gear, to thereby lock rotation of the second gear, and when the screw is unfastened, freeing movement of the spring, to thereby release locking of the rotation of the second gear.