Abstract
The mode-conversion loss in the matching between the gaussian beam emanated from the gyrotron and the hybrid mode in the circular corrugated waveguide with the diameter of 2a is discussed. By numerical calculation, it is found that the loss considerably increases and optimum waist sizew 0 changes when TEM00 mode with the wavelength λ is injected with offset or tilt. By fitting numerical data to the polynomial function, it becomes evident that the scaling formulas of the losses for the off-axis shiftr d and for the tilt angle θ are derived to be 2.3(r d /a)2 – 2.2(r d /a)4 and 3.9(aα/λ)2 – 5.6(aθ/λ)4 for fixedw 0/a=0.643, respectively. To keep the mode-conversion loss ≤1% for the frequency of 168 GHz and 2a=88.9 mm, tilting angle and offset should be less than 0.1 degrees and 2.9 mm, respectively.
Similar content being viewed by others
References
Ohkubo, K., Kubo, S., Iwase, M., Idei, H., Sato, M., Shimozuma, T., Takita, Y. and Kuroda, T.,International Journal of Infrared and Millimeter Waves,15, 1507–1519, 1994.
Moeller, C., Prater, R., Callis, R., Remsen, D., Doanne, J., Cary, W., Phelps, R. and Tupper, M.,Proceedings of the 16th Symposium on Fusion Technology, vol. 2, 1040–1044 (Elsevier, Amsterdam), 1991.
Nagasaki, H., Zushi, H., Sato, M., Sano, F., Kondo, K., Sudo, S., Mizuuchi, T., Besshou, S., Okada, H., Iima, M., Kobayashi, S., Isayama, A. and Obiki, T.,Fusion Technology,26, 153–158, 1995.
Erckmann, V., Gantenbein, G., Garaubner, T., Kasparek, W., Kunrić, H., Müller, G.A., Schüller, P.G. and Wagner, G.,Proceedings of the 19th International Conference on Infrared and Millimeter Waves, Sendai, 236–237, 1994.
Thumm, M. and Kasparek, W.,Fusion Engineering and Design,26, 291–317, 1995.
Abrams, P.L.IEEE Journal of Quantum. Electronics,QE - 8, 838–818, 1972.
Roullard, E.P. and Bass, M.,IEEE Journal of Quantum Electronics,Q13, 813–818, 1972.
Yariv, A.,Quantum Electronics, (Wiley, New York), 1975.
Doanne, J.Infrared and Millimeter Waves, Chapter 5, Propagation and mode coupling in corrugated and smooth-wall circular waveguides, p123–170 (Academic Press, New York), 1985.
Makowski, M., Private Communication inInternational Workshop on ECH Transmission System, Cocoa Beach Florida, 1995.
Vaganov, R.B.,Radio Engineering and Electronic Physics,18, 170–175, 1973.
Ohkubo, K., Kubo S., Iwase, M., Idei, H. Sato, M., Shimozuma, T., Takita, Y., and Kuroda, T.,Proceedings of the 18th Symposium on Fusion Technology, vol. 1, 513–516 (Elsevier, Amsterdam), 1995.
Rebuffi, S. and Crenn, J.P.,International Journal of Infrared and Millimeter Waves,10, 291–311, 1989.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ohkubo, K., Kubo, S., Idei, H. et al. Coupling of tilting Gaussian beam with hybrid mode in the corrugated waveguide. Int J Infrared Milli Waves 18, 23–41 (1997). https://doi.org/10.1007/BF02677895
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02677895