Planar Probe Coaxial-Waveguide Power Combiner/Divider

A novel axially symmetric oversized coaxial waveguide power combiner/divider, which utilizes a planar probe array to transform multiway input to a central oversized coaxial waveguide, is presented in this paper. The use of a coaxial waveguide allows standard transverse electromagnetic design theory to be used, and the characteristics of the coaxial taper transition and the planar probe array are analyzed in detail. A design procedure is also established for the structure. A ten-way planar probe coaxial-waveguide power combiner/divider over the Ku-band is designed and measured. The measured results show a reasonable agreement with the simulated results. The measured 15-dB return-loss bandwidth is approximately 4.3 GHz, and a maximum amplitude imbalance of +/- 1 dB and a phase imbalance of +/- 5 degrees are observed in the 11.5-16-GHz band. Furthermore, the isolation between the peripheral ports is also discussed.