High-Power Microwave Generation from a Virtual Cathode Device

Abstract
A relativistic electron-beam-driven virtual-cathode device has produced 500±130 MW at 17 GHz and 100±30 MW in the band from 30 to 40 GHz on a single typical machine firing. Computer calculations demonstrate that the source of the 17-GHz component is the reflexing of coherent electron bunches between the real and virtual cathodes. Oscillations in the virtual cathode and harmonic generation associated with reflexing electron bunches cause the higher-frequency components.