High-power single-mode microwave generation by coaxial vircator

Microwave oscillators based on a virtual cathode (vircators), as a rule, produce high-power microwaves up to several gigawatts. However, the efficiency of most of vircators is low and is a few percent due to the nonlinearity and complexity of the electron beam-to-electromagnetic wave energy conversion. The second problem with vircators is their rather wide radiation spectrum (-5-10 % of the central frequency) and multimode oscillation. Attractive features of vircators as high-power microwave (HPM) sources are the capability for operation with no external magnetic field and compactness: the length of electron interaction with an electromagnetic field is comparable with the radiation wavelength. The proposed configuration of a coaxial vircator with radial electron beam injection and electrodynamic feedback allows for the above shortcomings.