Junction discontinuity effect in multi-element coupled lines and its compensation

In multi-element coupled lines, the effect of junction discontinuity is unavoidable. These are found prominent in the high power coupled lines for HF and VHF applications because of larger structural dimensions. For the development of a 200kW tandem 3±0.2dB ultra-wideband hybrid coupler, design and simulation of a 3-elements 8.34±0.2dB coupled section is performed. In simulation results, coupling and output parameters of the designed coupled section are found significantly deteriorated from the theoretical prediction. The problem is investigated and found associated to the effect junction discontinuity. Junctions that are employed to join the elements produce undesirable reactive effect known as junction discontinuity effect. An analysis of the junction discontinuity effect in multi-element coupled lines and its compensation using novel approach is presented.