Design and experiment study of coaxial fin-inserted TEM－TE11 mode converter

The design and the measurements of the coaxial fin-inserted mode converter are presented. It is shown that with four metal fins inserted in the coaxial waveguide, the TEM mode is converted to coaxial TE11 mode and outputted with different phases, and finally, it forms a TE11 conventional circular waveguide mode. Moreover, four matching metal poles were designed to compensate for the reflection from inserted fins. The measured radiation patterns of the mode coveter agree well with the calculated results, which indicates that the out-put modes of the mode converter are the same as the simulated results. The experiment demonstrates the feasibility of the coaxial fin-inserted mode converter.