Analysis and Design of TE11-to-HE11 Corrugated Cylindrical Waveguide Mode Converters

A theoretical parametric study is given of a TE₁₁-to-HE₁₁ mode converter consisting of a section of cylindrical corrugated waveguide with varying slot depth. The analysis makes use of modal field-matching techniques to determine the scatter marks of the mode converter from which we deduce its propagation properties. It is shown that a mode converter consisting of only five slots achieves a return loss better than 30dB over the band 2.7<ka<3.8 (where a is the internal radius of the waveguide) with the HE₁₁ mode in the balanced conditions at ka=2.9. The predicted results are in very good agreement with experimental data.