A Novel High-Efficiency Segmented Design Method for High-Power Serpentine Shaped Mode Converter

Abstract

A segmented design scheme based on the iterative approach is proposed for the design of high-power serpentine shaped TM01–TE11 mode converter. It is found that the maximum electric field strength ( $E_{\mathrm {max}}$ ) in a serpentine shaped mode converter is related to the power ratio of the TM01 and TE11 modes at crux positions where the two modes have phase difference of $n\pi $ . Moreover, the bending direction of the serpentine axis at the crux positions needs to be adjusted to ensure high-efficiency power conversion from TM01 to TE11. By dividing the serpentine converter into several segments at the crux positions, and specifying the power ratio of the TM01 and TE11 modes, an improved iterative method using phase self-adaption and phase normalization is proposed for the design of the segmented serpentine structures with the desired $E_{\mathrm {max}}$ . For demonstration, a tri-bend TM01–TE11 mode converter was designed at $X$ -band for the specified $E_{\mathrm {max}}$ of 5 GW power input. Both the simulated and tested results of the conversion efficiency and electric field distribution are consistent with the theoretical predictions. Due to a quick estimation of the maximum power handling capacity of a serpentine shaped mode converter with arbitrary diameter, the proposed method has the merits of quick convergence and high computation efficiency.