Efficiency Improvement of a Klystron-Like Relativistic Traveling Wave Oscillator With a Ridge Extractor and Permanent Magnet Over the Dual Cavity Extractor

We investigate a klystron-like relativistic traveling wave oscillator (KL-RTWO) with a ridge extractor packaged with a permanent magnet (PM) in simulation and experiment. The result shows that the KL-RTWO with a ridge extractor is more efficient than that with a dual cavity extractor. In particle-in-cell (PIC) simulation, the ridge extractor enhances the beam-wave interaction remarkably by the electric field redistribution and matching the phase between the fundamental current harmonic and RF electric field, and the conversion efficiency is increased by 36%. In experiment, the KL-RTWO with a ridge extractor packaged with a 0.5 T PM generated 1.04 GW microwave power with conversion efficiency of 43% at the diode voltage 520 kV.