Circular waveguide TM₀₁−TE₁₁ mode converter

This paper presents a novel approach to the design of waveguide mode converters that differs from the commonly used double-bend and triple-bend structures. The approach employs sinusoidal function curves to construct the mode converters, and is based on the coupled wave theory. Furthermore, an optimization program for the structural parameters of the mode converters is developed. The differential evolution algorithm is employed to optimize the geometric structure of the circular waveguide TM<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</inf> – TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> mode converter with a center frequency of 9.7 GHz, with the objective of achieving a maximum mode conversion efficiency of 99% or above. The efficacy of this approach is validated through simulation using HFSS simulation software. The results demonstrate that this mode converter exhibits high conversion efficiency. The highest mode conversion efficiency is 99.59%, and the bandwidth with conversion efficiency above 90% is approximately 1.19 GHz. The mode converter exhibits high conversion efficiency and a wide bandwidth, and is compatible with both input and output coaxial standards.