Numerical Simulation Study and Preliminary Experiments of a Coaxial Vircator With Radial Dual-Cavity Premodulation

Numerical and experimental studies on a coaxial vircator with radial dual-cavity premodulation are presented. The physics of mechanisms on microwave frequency determination and effects on microwave generating efficiency are discussed. It is proved that the microwave frequency is mainly determined by the modulation frequency, while the optimum operating frequency is determined by the intrinsic frequency of the beam itself. When the two frequencies match, the maximum efficiency is yielded. A structure capable of generating 6.0 GW microwave, 17% efficiency, and 50% frequency tuning bandwidth has been obtained by numerical simulations. The preliminary experiments were carried out on the MC55 accelerator. A 2.0 GW output microwave was experimentally obtained and the corresponding device efficiency is about 7%.