Enhancing Vircator Efficiency Using Tapered Reflectors With Increasing Interreflector Distance

The effectiveness of virtual cathode oscillator (Vircator) applications has been restricted due to the low efficiency in converting the electron beam to microwave. This research introduces the design of an axial Vircator that achieves higher power output by using reflectors in the drift area. The paper outlines the methodology for enhancing the reflector location, radii, and interreflector distances through the design process. While previous research works have been carried out on optimizing reflector radii and positioning, this work includes an optimization based on analytical expressions. This gives way to different placements of reflectors in which the “interreflector distance” increases with decreasing radii, which has not been studied before. The tapered radius and the increasing interreflector distance enhance the electrostatic focusing of the beam. The simulation findings, conducted using CST Microwave Studio, demonstrate that the average efficiency of the axial Vircator increases from 0.3% to 10.41%, and its average power output increases from 36.9 MW to 1.3 GW when five reflectors were added. The radius and distance between reflectors are increased as more reflectors are added in the drift region. The enhanced Vircator operates at a voltage of 511 kV and a peak current of approximately 24 kA, resulting in a dominant frequency of around 3.1 GHz. These findings indicate a notable improvement in Vircator performance, providing a route to enhance the efficiency of microwave device applications.