Full-wave design of broad-band compact waveguide step-twists

Rectangular waveguide twists are components that provide an on-axis rotation of the transverse waveguide section. In this letter, a step twist configuration, obtained by the direct connection of rotated rectangular waveguide lengths, is considered. The advantages of this configuration are the easy manufacturing with tight control on the relative rotation angles and the reduction of the overall dimensions. By means of a full-wave synthesis approach various wide-band devices were designed and reported in the letter. In particular, a couple of 45° twists was manufactured and integrated in the Ka-band OMT realized for the SPOrt project. The experimental results match the excellent predicted data.