A Ku band high efficiency coaxial relativistic backwardwave oscillator with low magnetic field

A Ku band coaxial relativistic backward wave oscillator (RBWO) with low magnetic field is presented in this paper. This RBWO works at coaxial TM01-mode which contains two-segment slow wave structures (SWSs). The first segment SWS mainly modulates the intense electron and the second one mainly extracts the microwave energy. By introducing pre-modulate using an asymmetry reflector, the modulation depth is improved. By optimizing the length of the drift between SWSs, the field distribution is optimized and the axial electric field intension of the extract SWS is farther improved. The efficiency of the RBWO is improved. Finally ,when the magnetic field is 0.6 T，the diode voltage is 490 kV，the diode current is 7.5 kA, a 1.27 GW microwave is obtained with an efficiency of 35% and a frequency of 14.7 GHz.