Highly Effective, Repetitive Nanosecond-Range Ka-band BWO

The quasi-stationary mode of operation of a high-efficiency 38-GHz nanosecond relativistic microwave backward-wave oscillator at a pulse repetition rate of 10 Hz has been demonstrated. A hybrid modulator based on an SM-3N SOS driver and on an energy compression unit containing a pulse-forming line and a spark gap was used to produce 5-ns electron-beam-accelerating pulses of the trapezoidal shape. Optimization of the energy exchange between the weakly magnetized electron flow and the oncoming harmonics of the TM
₀₁
wave inside the periodic slow-wave structure has made it possible to achieve a peak power of ~170 MW for 4-ns microwave pulses at an electron efficiency no less than 30-35%.