A Novel Method to Depress Higher Order Mode Generation in MILO

Generating higher order mode microwave due to asymmetric beam emission or slightly asymmetric structure in MILO device is common, which puzzled a lot of researchers. A novel method to depress the higher order mode generation in MILO device is put forward for the first time. The excitation of the higher order modes was depressed by adjusting the slow wave structure, and a high power microwave in purified TEM mode was obtained. High frequency analysis and PIC simulation were carried out. The simulation results revealed that the novel MILO device oscillates at mode and successfully depressed the higher order mode generation. Employing an electron beam of 480 kV, 46 kA, and a TEM mode high power microwave with an output power of 734 MW, a frequency of 3.54 GHz was obtained in contrast with the original device with a mode output microwave frequency of 3.68 GHz.