C-Band High-Power-Capacity Rectangular Waveguide TE₁₀ to Circular Waveguide TM₀₁ Mode Converter

A rectangular waveguide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{10}$</tex> to circular waveguide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TM}_{01}$</tex> mode converter is designed, which achieves high-efficiency conversion from rectangular waveguide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{10}$</tex> mode to circular waveguide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{01}$</tex> mode. By coupling two <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{10}$</tex> mode signals with 180° phase difference from rectangular waveguides at the circular waveguide port to excite TM01 mode, the structure maintains coaxial alignment between input and output ports. CST simulation results demonstrate that at the central frequency of 5.31 GHz, the converter exhibits conversion efficiency exceeding 99.98%, return loss below −31 dB, and a bandwidth of approximately 0.8 GHz when maintaining conversion efficiency above 90%. Chamfering treatment at the coupling region effectively reduces electric field intensity and enhances power handling capacity. With 0.5 W input power, the maximum electric field strength remains below <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1681\ \mathrm{V} / \mathrm{m}$</tex>, corresponding to a power capacity of approximately 1.8 GW.