S-Band Bifrequency MILO With Improved Performance

In this article, we present an improved design of a bifrequency magnetically insulated line oscillator (BFMILO). We begin with design expressions for the output section parameters considering transmission line impedance across the extractor. This helps in proper impedance matching so as to maximize the RF power exchange arising out of the intense beam-wave interaction. In order to reproduce more RF energy from the space charge limiting current at the load, a metal plate is inserted inside the collector cavity depth. Two tapered extractor vanes are imposed at the load side along with the stub, to enhance the RF power extraction and proper RF coupling. Simulation results show that the modified collector design generates an RF output power of ~3.8 GW at dual operating frequencies, namely, 3.05 and 3.32 GHz. The peak power conversion efficiency was estimated as 16.17% with an applied voltage of 500 kV and a beam current of 47 kA.