A High-Efficiency Ridged Magnetically Insulated Transmission Line Oscillator

In this study, we investigate the effect of the inclusion of ridged disk vanes on the operation of a magnetically insulated transmission line oscillator (MILO), using a combination of “cold” (without electron beam) and “hot” (with electron beam) simulations. Cold simulation shows that the inclusion of ridged-disks in a ridged MILO (RMILO) enhances its slow wave structure's (SWS's) coupling impedance, thus improving its power efficiency. Moreover, since the ridges' effect on frequency is weak, the MILO's inherent tunability is maintained. In hot simulation, the RMILO obtains a 3-dB tunable frequency range of 0.96-2.18 GHz with an applied voltage of 603 kV, in contrast to the 1.04-2.01-GHz range obtained with a conventional MILO (CMILO), owing to the former's improved power efficiency. With this voltage, the device generates the high power microwave (HPM) with a maximum output power of 7.1 GW at a frequency of 1.40 GHz, corresponding to a power efficiency of 22.6%. The maximum power efficiency of 24.5%, corresponding to a 13.5-GW output, was obtained by increasing the applied voltage to 807 kV, an increase of 20.2% compared to the power efficiency obtained with a CMILO in the same condition.