W-Band Low-Loss Eight-Way Radial-Waveguide Power Divider Based on Coaxial Mode Transition

A W-band eight-way radial-waveguide power divider with low insertion loss and high power-combining efficiency has been proposed in this paper. The coaxial waveguide has been utilized in the eight-way radial-waveguide power divider as a transition from the rectangular waveguide to radial waveguide. The structure of the coaxial mode transition from the rectangular waveguide to radial waveguide is simple, and its electrical length is much shorter than others’ mode transition, which results a low insertion loss and high power power-combining efficiency. The microwave signal was inputted from the rectangular waveguide (TE10 mode) and transmitted to the radial waveguide (cylindrical TEM mode) through the coaxial waveguide (TEM mode). Finally, the signal in radial waveguide is divided into eight ways with equal power and equal phase by the eight output standard rectangular waveguide. This all-metal waveguide multi-way power divider demonstrates the advantages of easy design and fabrication, large and arbitrary number of combination ports, and a simple and compact structure. To verify the presented power divider, a W-band eight-way power divider is fabricated and measured. The measured results show that, over the frequency range from 82 to 110 GHz, the measured input return loss is greater than 15 dB, the measured average insertion loss is about 9.4 ± 0.5 dB, the phase imbalance is about ± 5°, and the power-combining efficiency is about 91%.