Study of high-power microwave generation in the coaxial vircators with a divergent beam

The results of experimental and theoretical investigations of microwave excitation in coaxial vircator with a symmetric radially divergent beam are presented in the paper. The influence of system geometry and beam parameters on the formation of virtual cathode and emission characteristics has been conducted. Theoretical studies have been carried out using numerical simulation program based on particle-in-cell method. The dependence of current, frequency characteristics and radiation power on geometry and beam parameters has been obtained experimentally and numerically. In the experiments the radiation power with a narrow radiation pattern up to 300 MW at the frequency of 3 GHz has been obtained.