Simulation of an FEA Electron Gun for TWT

Summary form only given. In contrast with conventional thermoionic cathodes traveling wave tubes (TWT), the TWT employing field emitter array (FEA) cathodes are expected higher efficiency, with more compact size and lighter weight. When applying FEAs as the cathodes of the TWTs, many problems are to be considered and among them, the beam control and focusing of electron guns is the most principal. An FEA electron gun used for TWT was designed in the research. The designed model, including cathode, extracting electrode, focusing electrode and anode, was simulated by using the three-dimensional electromagnetic program MAFIA, the electric field distribution and the electron beam trajectory in the interior region of the gun were obtained. In the simulation, all the electrons were assumed to be emitted from the gate plane of the FEA, and the initial velocity and the scattering angle of electron were taken into account