Peculiarities of Backward-Wave Amplification by Relativistic High-Current Electron Beams

Microwave amplification in relativistic backward wave oscillator operating below its self-excitation threshold is considered. The conditions that allow to achieve high gain provided with stable operation of the backward wave amplifier (BWA) were found. Several schemes of use of the relativistic BWA providing high power microwave amplification were studied. It is shown that employing a BWA in regenerative amplification regime allows to obtain more than 40 dB gain with efficiency over 20%.