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Title: A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4945645· OSTI ID:22599151
; ;  [1]
  1. College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM{sub 01}. The existence of TM{sub 01} mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

OSTI ID:
22599151
Journal Information:
Physics of Plasmas, Vol. 23, Issue 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English