Generation of high-power microwave pulses of ultrashort duration

Experimental studies have been performed of the virtode, a transit-type high-power microwave pulse oscillator with a supercritical current of a relativistic electron beam (REB), and controllable frequency and output amplitude. As a result of mode selection of charge density oscillations in the electron beam, the virtode output frequency has appeared to be 4 to 5.5 GHz. Changing the phase of the UHF feedback voltage (within ±π) results in a 8 dB variation of the radiated microwave power. The highest electron efficiency of the virtode reached 17% for a pulsed microwave power of ∼ 600 MW. The dominant role of the beam mode selection in the drift region of the REB for the phase and frequency control has been demonstrated for a vircator-based combined electrodynamic system. The frequency tuning range may exceed one octave in systems incorporating a BWO. The absence of resonant elements in the virtode driving circuit makes it possible to use them for developing phase-locked high-power arrays.