Design of bent circular waveguide TE01-to-TM11 mode converter

Based on the coupling wave theory and principle of the mode converter with exponential profile, we design a 16mm circular waveguide TE
₀₁
-to-TM
₁₁
mode converter which has a bend angle of 90 degree. The optimal geometry parameters of the mode converter are given and analyzed by numerical calculation. The conversion efficiency of waveguide axis in exponential curvature converter is about 99.65%, at 18.5GHz, with bandwidths (for mode-conversion efficiency > 95%) of 27%. Simulated results from CST agree well with the numerical calculations.