2D and 3D Design Simulations of Diode-Type Magnetron Injection Gun for 28Ghz Gyrotron

This paper presents the 2D and 3D design simulations of a diode-type MIG (Magnetron Injection Gun) for a 28 GHz fundamental harmonic gyrotron operating in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{0,2}$</tex> mode. The MIG is designed to deliver up to 15 kW of output power, with a beam voltage <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 25 \text{kV}$</tex> and a beam current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 2 ~\mathrm{A}$</tex>. An axial magnetic field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 1.014 ~\mathrm{T}$</tex> is required for fundamental harmonic operation. The design has been optimized to achieve a beam compression ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 11$</tex>. The initial design approach involved analytical trade-off equations, followed by 2D and 3D simulations using EGUN and CST Particle Studio. Additionally, the results from both simulations, comparing the design validation, have also been presented.