BWO with an amplifying section

A backward wave oscillator (BWO) is an electron device in which an electron beam and an EM wave excited by this beam move in opposite directions. The BWO provides a maximum power at the output adjacent to the gun, while the maximum modulation of the electron beam is achieved near the collector. This is why BWOs have a relatively low efficiency. The analysis presented in this paper shows the possibility to increase the BWO efficiency by adding an additional section of a slow-wave structure, operating in the forward wave mode. The preliminary analysis of a two-section BWO in which the first section operates as a beam modulator and the second section converts the DC energy of the modulated beam into the microwave energy at the output of the device is detailed. The first section, operating in the backward wave mode, is loaded at both ends by matched severs, while the second section is connected to the matched output. The input end of the second section can also be loaded by a sever.