A Ka-band Transition from E-plane Waveguide to H-plane Waveguide

In this paper, A compact rectangular waveguide with 90° twist is proposed. The E-plane and H-plane waveguides are connected to a square waveguide in series. The cross-section of the square waveguide has the shape of a square with two diagonally corners cuts. It provides a 90°output polarization rotation to realize the transition from E-plane waveguide to H-plane waveguide. The advantages of this structure are the reduction of dimensions and the facilitation of fabrication. This paper presents a mechanically machined compact waveguide twist in the Ka-band. Measurements of a WR-28 twist exhibit a return loss near 20dB and an insertion loss of 0.6dB from 28GHz to 35GHz. The experimental data are in good agreement with the predicted results.