Terahertz Research Center， School of Electronic Science and Engineering， University of Electronic Science and Technology of China， Chengdu 610054， China
Supported in part by the National Key Research and Development Program of China under Grant 2017YFA0701000, in part by the Natural Science Foundation of China (61988102) and the Fundamental Research Funds for the Central Universities under Grant A03018023601003.
The electromagnetic characteristics of the double confocal waveguide for a gyro-TWT is investigated in details. The eigenvalue and the field distribution of two kinds of steady-state modes in a double confocal waveguide, namely the superposition mode and the ring mode, are calculated with the scalar formulation of Huygens’ Principle, the theoretical results agree well with those from the commercial CST software. When the anti-phase superposition mode TE06 mode is chosen as an operating mode in a gyro-TWT, the diffractive loss of the potential parasitic modes is far greater than that of the operating mode. It means that the potential parasitic modes can be suppressed by means of its own diffractive loss in a double confocal waveguide. The mode density in a double confocal waveguide is higher than that in a single confocal waveguide, but far lower than that in a cylindrical waveguide. Compared to the single confocal waveguide, a higher beam-wave interaction efficiency can be obtained in the double confocal waveguide for a gyro-TWT, it is an appropriate choice to choose a double confocal waveguide as the beam-wave interaction structure in a gyro-TWT.
ZHANG Chen, WANG Wei, SONG Tao, HUANG Jie, CAO Yi-Chao, LIU Di-Wei, HU Min, ZHANG Kai-Chun, WU Zhen-Hua, ZHOU-Jun, ZHONG Ren-Bin, ZHAO Tao, GONG Seng, LIU Sheng-Gang. Detailed investigations on double confocal waveguide for a gyro-TWT[J]. Journal of Infrared and Millimeter Waves,2020,39(5):547~552Copy