A novel wideband radial waveguide power combiner using coaxial-to-ridge waveguide transitions

A novel wideband eight-way radial waveguide power combiner has been proposed in this paper. The proposed radial waveguide power combiner consists of a commercial N-type connector, a regular-octagon waveguide cavity, eight matching circuits, and eight coaxial-to-ridge waveguide transitions. The introduction of matching circuits is used to improve matching performance in the regular-octagon waveguide cavity. Besides, in order to guarantee the bandwidth performance and facilitate applications, eight coaxial-to-ridge transitions as output ports were also designed to connect ridge ports of the radial waveguide power combiner. Therefore, the overall performance of the proposed waveguide power combiner is enhanced over the wideband range. For validation, a sample eight-way radial waveguide power combiner has been designed, fabricated, and measured. The measured results show that the return loss (S₁₁) and insertion loss (S₂₁) are better than 20 dB and 0.5 dB, respectively, in the whole frequency range from 4 to 8 GHz (with 66.6% fractional bandwidth). The measured results reasonably agree well with the simulation ones. Compared with some other radial waveguide power combiners, the completed radial waveguide power combiner exhibits lower return loss, lower insertion loss, more compact size, and prominent bandwidth performance.