Optimal Design of a Coaxial Cavity Based on Quality-Factor Maximization for High-Power Coaxial Magnetron in $X$ -Band

This paper presents the synthesis of a coaxial cavity for high-power X-band coaxial magnetron. In the proposed design, cavity parameters corresponding to optimum quality factor are determined. The quality factor of the coaxial cavity for the TE
₀₁₁
mode is obtained analytically and verified by CST and HFSS simulations. The maximum value of the quality factor achieved is 17150 for the TE
₀₁₁
mode at an operating frequency of 9.32 GHz, considering the cavity walls to be made of copper. Resonant frequencies of various competing modes (such as TE
₁₂₁
, TE
₂₂₁
, and so on) of the operating TE
₀₁₁
mode are also determined and shown using a mode diagram. The dominant interfering mode, TE
₁₂₁
, is suppressed considerably using an auxiliary cavity filled with lossy dielectric material. The quality factor of the unwanted TE
₁₂₁
mode is reduced by 75.49%, while keeping quality factor of the desired TE
₀₁₁
mode unaffected. A significant reduction in the quality factors of other unwanted modes is also observed.