Characteristics of a 4, 5 and 6 Ghz bands oversize circular bending waveguide

Abstract

AbstractTheoretical investigations and results of a trial test on the oversized circular waveguide bend for the 4, 5, and 6 GHz bands are reported. Degradation of cross polarization isolation in the waveguide bend is shown to be caused not only by the distortion of the guide diameter but also by the higher‐order modes generated at the bend. In theory, degradation can be improved by connecting an elliptical waveguide with a rotating flange to the bent waveguide and rotating it by a given angle. We show the range of the rotating angle of the elliptical waveguide in which cross polarization isolation is improved. Measured electrical characteristics of the circular waveguide bend made for trial are compared with computed values and the analytical method is proven to be effective. It is found that the circular waveguide bend can be used in practice if it is combined with an elliptical waveguide with a rotating flange and TM mode filter.