Key-Holes magnetron design and multiphysics simulation

This paper describes the design and the characterization of an 8 slots resonant cavities Magnetron, which undergoes the thermal-structural effects due to the cathode heating. The proposed study involves Thermal Stress (TS), Eigen-frequency (EF) and Particle Tracing (PT) analysis based on a COMSOL Multiphysics (MP) simulation. Magnetrons are well known and more utilized High Power (HP) Radiofrequency (RF) Vacuum Tube (VT) oscillators. In order to generate high power signals, they employ thermoelectric cathodes which can reach very high temperatures, necessary to produce the enough surface charge density [1]. Since device efficiency depends critically to the operating temperature, a Multiphysics (MP) approach has been adopted. A PT and an EF analysis with a computation of the power density distribution of the electric field resonant modes and particle trajectories and velocities have been performed, considering the thermal-structural modifications induced by the cathode heating to the entire structure.