Design of X-band RBWO output system

In order to realize the output requirements of RBWO, a high-power microwave radiation system is designed for the X-band placed in the outer cavity, including a mode converter and a compact antenna output structure. The electromagnetic simulation software was used to numerically simulate and optimize the mode converter and antenna structure. The results show that the X-band coaxial TEM-circular waveguide
$TM_{01}$
mode converter structure has high conversion efficiency within the frequency range of interest, and the conversion efficiency of the mode converter is 99.54% at the center frequency of 10.1GHz, and the conversion efficiency of the mode converter is greater than 98% in the 500MHz frequency range. Through the numerical simulation and optimization of the antenna output structure, the antenna pattern gain simulation result is 18.86dB at 10.1GHz (center frequency), which meets the requirements of antenna miniaturization and lightweight design. The design idea and structure can be applied to the dual-frequency antenna radiation system of RBWO.