Coupling filter for communications system - has triple-cavity filters connected between two three=DB couplers, to give required characteristics

摘要

The coupling filter, for a communications system, consists of two 3dB couplers connected together by two identical filters. The filters (21, 22) are located between the two couplers. Each coupler consists of a hole (7) in the wall separating the two channels (3, 4) (cut parallel to one another in a metal block). A small post (8) in this hole provides capacities matching whilst steps (9, 10) on the outer walls of both channels act as impedance transformers. Each filter consists of 3 cavities separates by transverse walls (26) with holes (28) making coupling irises. Each cavity has a turning screw (29).