Design Equations of Arbitrary Power Split Ratio Waveguide T-Junctions Using a Curve Fitting Approach

Design equations have been developed for the design of an H-plane rectangular waveguide T-junction with an arbitrary power split. These design equations were derived using curve fitting or data produced from a large number of EM simulation runs. A design procedure has been successfully developed and resulted in scalable, practically manufacturable structures. Various types of discontinuities were Judiciously placed in the junction to provide adequate degrees of freedom and concurrently achieve diverse design goals. Added discontinuities included wedges and diaphragms which have been implemented as an integral part of the prescribed structures. For demonstration, T-junction designs at Ku-band have been fabricated and tested, which have adequate bandwidth performance covering the US-DBS 12.2-2.7 GHz frequency range. Both excellent match at the input port and in-phase flat power-split ratio over a relatively wide band at the output ports were successfully achieved-an essential requirement for high-performance antenna feeds. The dimensional tolerance of the developed design vas also thoroughly investigated using extensive sensitivity analysis, and the developed structures proved to be appropriate for low-cost high-volume fabrication methods such as casting. (C) 2008 Wiley Periodicals. Inc. Int J RF and Microwave CAE 19: 91-98. 2009.