Design of an overmoded bend coaxial waveguide

This paper presents a novel type of overmoded bend coaxial waveguide with a 45 bend angle at a center frequency of 4.0 GHz. The basic principle of the overmoded bend coaxial waveguide is introduced, and the condition of realizing high efficiency turning transmission and a mode problem on the overmoded waveguide are analyzed. The simulation result indicates that, at the center frequency, the transmission efficiency of the fundamental mode is over 99% and the reflectance is about 0.04. In the range of 3.8 to 4.2 GHz, the transmission efficiency of the fundamental mode is over 95% and the reflectance is below 0.22. The overmoded bend coaxial waveguide with a turning radius about 80 mm, which has the features of simple structure, small turning radius and flexible bend angle, and also needs no media support, is suitable for turning transmission of the overmoded coaxial waveguide in high power microwave feeder system.