An Improved -Band Magnetically Insulated Transmission Line Oscillator

An improved K_u-band magnetically insulated transmission line oscillator (MILO) was designed and presented in this paper. To eliminate the electrode erosion in the load region, an improved limited load is presented. Theoretical calculations show that both the current density and the energy deposition density of the improved load are much smaller than those of the traditional plane diode load, so the electrode erosion can be eliminated or greatly reduced. An improved coaxial extractor with a gradient inner conductor is introduced to achieve efficient microwave extraction and a single coaxial TEM output. Simulation results show that the right amount of microwave reflection generated by the gradient inner conductor helps to strengthen the oscillation of the resonant cavities and the beam-wave interaction, then enhancing the microwave output efficiency. The improved K_u-band MILO is optimized numerically with a particle-in-cell code. Typical simulation results show that when the input voltage is 450 kV, the beam current is 48 kA, and high-power microwave is produced with an average power of 2.7 GW, an efficiency of 12.5%, and a frequency of 12.5 GHz.