Journal of Infrared and Millimeter Waves, Volume. 41, Issue 2, 457(2022)

The multi-modes, multi-harmonics behavior of a THz large-orbit gyrotron

Qi-Xiang ZHAO1, Meng-Shi MA1, Xiang LI2、*, You LV1, Tian-Zhong ZHANG3, Lin PENG1, E-Feng WANG4, and Jin-Jun FENG4
Author Affiliations
  • 1School of Information and Communication,Guilin University of Electronic Technology,Guilin 541004,China
  • 2Research and Development Center,Dynex Semiconductor Ltd.,Lincoln,LN6 3LF,UK
  • 3School of Electronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu,610054,China.
  • 4National Key Laboratory of Science and Technology on Vacuum Electronics,Beijing Vacuum Electronics Research Institute,Beijing 100015,China
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    Figures & Tables(17)
    The LOG cavity profile from the longitudinal view
    The variation of the total quality factor,diffraction quality factor,ohmic loss quality factor and the oscillation frequencies of the designed modes with the azimuthal index(m)
    Radial distribution of the azimuthal electric field Eϕ for TEm,1 modes(m=4∼9). ϕ and r denotes the azimuthal and radial coordinate,respectively. Jm' is the first derivative of mth order Bessel function. Rw is the waveguide radius
    The starting current variation with external magnetic field,where the beam voltage is 250 kV,the pitch factor is 2.0
    The nonlinear output power and output frequency variation with the external magnetic field
    Dispersion diagram of the cylindrical waveguide modes and the synchronism condition when the external magnetic field is 2.71 T and 2.76 T
    The nonlinear output power and output frequency variations with the beam current when the magnetic fields for TE7.1, TE8.1, TE9.1 are 2.77 T,2.74 T and 2.71 T,respectively
    The electric field distribution of the TE9,1,1 mode obtained by CST simulation (a) the axial electric field distribution, (b) the transverse electric field distribution
    The spectrum of the output signal. The inset shows the variations of the mode amplitude of TE9,1,1 with time
    The output power and output frequency variations with the external magnetic field when the beam voltage is 250 kV and beam current is 3.0 A
    The transverse view of the electron beams when operating at different harmonics(a)the unperturbed large-orbit electron beams,(b)the azimuthal bunching at the 9th harmonic(when B=2.71 T),(c)the azimuthal bunching at the 8th harmonic(when B=2.73 T),(d)the azimuthal bunching at the 7th harmonic(when B=2.77T)
    The output amplitude variation with time when B=2.77 T and I=3 A. The inset is the spectrum of the output signal.
    The output power and frequency variation with wall conductivity when B=2.72 T and I=3A.
    The output power and output frequency variation with the beam current when the external magnetic field is 2.71 T,2.72 T,and 2.77 T,respectively
    The output power variation with time when B=2.72 T and I=4.5A. The inset is the spectrum of the output signal
    • Table 1. The geometric parameters of the LOG cavity

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      Table 1. The geometric parameters of the LOG cavity

      ParametersValue
      the length of the middle cylindrical waveguide L10 mm
      the radius of the middle cylindrical waveguide R1.1 mm
      the input radius of the input cone Rin0.8 mm
      the output radius of the input coneRout1.3 mm
      The angle between the input cone and middle cylindrical waveguide θ16°
      The angle between the output cone and middle cylindrical waveguide θ24°
    • Table 2. The comparison between the cold cavity analysis and hot cavity simulations

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      Table 2. The comparison between the cold cavity analysis and hot cavity simulations

      ParametersCold cavity simulationHot cavity simulation
      Oscillation Frequency/GHz464.82463.62
      Ohmic quality factor3 390.83 802.3
      Diffractive quality factor10 3284 484
      Total quality factor2 552.72 057.6
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    Qi-Xiang ZHAO, Meng-Shi MA, Xiang LI, You LV, Tian-Zhong ZHANG, Lin PENG, E-Feng WANG, Jin-Jun FENG. The multi-modes, multi-harmonics behavior of a THz large-orbit gyrotron[J]. Journal of Infrared and Millimeter Waves, 2022, 41(2): 457

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    Paper Information

    Category: Research Articles

    Received: Aug. 16, 2021

    Accepted: --

    Published Online: Jul. 8, 2022

    The Author Email: Xiang LI (xiang.li@dynexsemi.com)

    DOI:10.11972/j.issn.1001-9014.2022.02.012

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