Simulation of high injection efficiency of multibeam diode for Ka-band relativistic klystron amplifier

To generate annular multi-beam intense relativistic electron beams, a multi-beam diode of an Ka-band relativistic klystron amplifier is designed. The introduction efficiency and the quality of the electron beam are investigated by three-dimension particle in cell simulation. The simulation results show that the diode can generate 26 beams electron beams with high quality and introduction efficiency of about 99% by optimizing the key parameters of the multi-beam diode. The diode can be applied to multi-beam coaxial relativistic klystron amplifier with gigawatt-level output at Ka band.