Abstract
The gyro-TWT in a cylindrical waveguide of linearly-tapered cross section was analyzed for the gain-frequency response, using the Pierce-type gain equation. The taper in the waveguide cross section was adjusted for wide device bandwidths, either by changing the taper angle, while keeping the interaction length to be constant, or by changing the interaction length, while keeping the initial and final radii of the waveguide constant. Tapering led to the prediction of wide bandwidths, though at the cost of gain, as compared to a non-tapered device. The range of the DC background magnetic flux density relative to its grazing-point value was identified as a crucial parameter for large gains, with appreciable bandwidths, and minimum mode mixing in a tapered device, the latter in general facing more mode competition than a non-tapered device.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
B. R. Cheo and A. Rekiouak, “Linear and nonlinear analyses of a wideband gyro-TWT”, IEEE Trans. Electron Dev., vol. ED-36, pp. 802–810, 1989.
K. R. Chu, A. T. Drobot, V. L. Granatstein, and J. L. Seftor, “Characteristics and optimum operating parameters of a gyrotron traveling-wave amplifier”, IEEE Trans. Microwave Theory Tech., vol. MTT-27, pp. 178–187, 1979.
K. R. Chu, Y. Y. Lau, L. R. Barnett, and V. L. Granatstein, “Theory of a wide-band distributed gyrotron traveling-wave amplifier”, IEEE Trans. Electron Dev., vol. ED-28, pp. 866–871, 1981.
J. Y. Choe and H.S. Uhm, “Theory of gyrotron amplifier in disc and helix loaded waveguides,” Int. J. Electron., vol. 53, pp. 729–741, 1982.
S. J. Rao, P. K. Jain, and B. N. Basu, “Broadbanding of a gyro-TWT by dielectric loading through dispersion shaping”, IEEE Trans. Electron Dev., vol. ED-43, pp. 2290–2299, 1996.
J. Y. Choe and S. Ahn, “General mode analysis of a gyrotron dispersion relation”, IEEE Trans. Electron Dev., vol. ED-28, pp. 94–102, 1981.
K. C. Leou, D. B. McDermott, and N. C. Luhmann, Jr., “Dielectric-loaded wideband gyro-TWT”, IEEE Trans. Plasma Sci., vol. PS-20, pp. 188–196, 1992.
A. K. Ganguly and S. Ahn, “Large signal theory of two stage wide-band gyro-TWT”, IEEE Trans. Electron Dev., vol. ED-31, pp. 474–480, 1984.
S. Ahn, “Gain and bandwidth of a gyrotron amplifier with tapered rectangular waveguide”, Int. J. Electron., vol. 53, pp. 673–679, 1982.
G. S. Park, S. Y. Park, R. H. Kyser, C. M. Armstrong, A. K. Ganguly, and R. K. Parker, “Broadband operation of a Ka-Band tapered gyro-traveling-wave amplifier”, IEEE Trans. Plasma Sci., vol. PS-22, pp. 536–543, 1994.
G. S. Park, J. J. Choi, S. Y. Park, C. M. Armstrong, A. K. Ganguly, R. H. Kyser, “Gain broadening of two stage tapered gyrotron traveling wave amplifier”, Phys. Rev. Lett., vol. 74, pp. 2399–2402, 1995.
S. J. Rao, P. K. Jain, and B. N. Basu, “Two-stage dielectric-loading for broadbanding a gyro-TWT”, IEEE Electron Dev. Lett., vol. 17, pp. 303–305, 1996.
A. J. Sangster, “Small-signal analysis of the travelling-wave gyrotron using Pierce parameters”, Proc. IEE, Pt. I, vol. 127, pp. 45–52, 1980.
A. W. Fliflet, “Linear and nonlinear theory of the Doppler-shifted cyclotron resonance maser based on TE and TM waveguide modes”, Int. J. Electron., vol. 61, pp. 1049–1080, 1986.
B. N. Basu, Electromagnetic theory and applications in beam-wave electronics, World Scientific, Singapore, 1996.
J. R. Pierce, Traveling-Wave Tubes, Van Nostrand, New York, 1950.
J. M Baired and W. Lawson, “Magnetron injection gun (MIG) design for gyrotron applications”, Int. J. Electron., vol. 61, pp. 953–967, 1986.
Lawson, “Theoretical evaluation of nonlinear tapers for a high-power gyrotron”, IEEE Trans. Microwave Theory Tech., vol. MTT-38, pp. 1617–1622, 1990.
X. Cheng-He and L. Zhang, “Theoretical analysis of gyrotron amplifier with undulated waveguide”, Int. J. Electron., vol. 57, pp. 1175–1189, 1984.
R. W. Grow and U. A. Shrivastava, “Impedance calculations for travelling wave-gyrotrons operating at harmonics of the cyclotron frequency in magnetron-type circuits”, Int. J. Electron., vol. 53, pp. 699–707, 1982.
C. K. Chong, D. B. McDermott, A.T. Lin, W. J. Dehope, Q. S. Wang, and N. C. Luhmann, Jr., “Stability of a 95GHz slotted third-harmonic gyro-TWT amplifier”, IEEE Trans. Plasma Sci., vol. PS-24, pp. 735–743, 1996.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Agrawal, M., Sridhar, T.R., Jain, P.K. et al. Waveguide Cross Section and Background Magnetic Field Tapers for Broadbanding a Gyro-TWT. International Journal of Infrared and Millimeter Waves 21, 1255–1267 (2000). https://doi.org/10.1023/A:1026448000149
Issue Date:
DOI: https://doi.org/10.1023/A:1026448000149