Patent ID: 7449981
Filing Date: 2008-11-11
Classification: H01P

Abstract:
1. A variable frequency band filter comprising: a housing; at least one resonator rod extending from the bottom surface of the housing; a first resonance tuning screw coupled to an outer peripheral surface of the housing in such a manner that the first resonance tuning screw can be moved linearly, an end of the first resonance tuning screw being disposed adjacently to the resonator rod; a tuning support rotatably coupled to the outer peripheral surface of the housing; a support plate extending from an outer peripheral surface of the tuning support, the support plate having a surface facing the other end of the first resonance tuning screw and being adapted to be rotated about the tuning support, as the tuning support is rotated; and a support spring having an end supported on the outer peripheral surface of the housing and the other end supported on the other end of the first resonance tuning screw, the supporting spring providing an elastic force in such a direction that the end of the first resonance tuning screw is moved away from the resonator rod, wherein as the tuning support is rotated in one direction, the end of the first resonance tuning screw is moved by the support plate in a direction approaching the resonator rod, and as the tuning support is rotated in the other direction, the end of the first resonance tuning screw is moved away from the resonator rod, thereby varying the resonance frequency band.