A microsecond-pulse-length, frequency stabilized virtual-cathode oscillator using a resonant cavity

Experiments at the microsecond pulse length have demonstrated that the virtual-cathode oscillator generates narrow-band (0.3% bandwidth) microwave pulses when the virtual cathode is surrounded by a resonant cavity and is driven by an appropriate electron beam. This result is a significant departure from the behavior of a free-running virtual-cathode oscillator where the frequency depends on the (current [density).sup.1/2]. This paper describes the long-pulse experimental results.