A Compact Vircator with Feedback Annulus Operated in Quasi-Single TM₀₁ Mode Within C Band

An axially extracted virtual cathode oscillator (vircator) with a feedback annulus is proposed and configured through particle-in-cell simulation. This compact device needs no guiding magnetic field. Its experimentally radiated microwave is measured to be of quasi-single TM₀₁ mode with a frequency range of 4.41-4.69 GHz and a power level of above 300 MW, when the diode voltage ranges in 400-480 kV and the beam current in 20-25 kA; this conforms the simulation results.