Title :
Mode generators for high order rotating gyrotron modes
Author :
Wagner, D. ; Blank, M. ; Chu, T.S. ; Felch, K. ; Mizuhara, M. ; Kasparek, W.
Author_Institution :
CPI Wireless Solutions, Palo Alto, CA, USA
Abstract :
In order to cold test the performance of quasi-optical mode converters of gyrotrons, high order gyrotron cavity modes have to be excited at low power levels. There are several approaches to generate such modes. One is to use combined sections of periodically-perturbed-waveguide-wall converters, which step-wise convert from fundamental to high order waveguide made. Since recent gyrotrons use very high order modes such converters would become extremely long and therefore narrow band, as well as difficult to build mechanically. The most promising and compact solutions are mode generators where the resonant cavity is directly excited through coupling holes in the waveguide wall. One such solution is to use coupled cavities where the fundamental TE/sub 1,1/ input mode is coupled through an iris to an intermediate TE/sub 1,n/ cavity which is finally coupled to the high order cavity mode through a fine electroformed screen. This paper focuses on an even simpler quasi-optical solution where a free space Gaussian beam is directly coupled to the high order gyrotron mode through a translucent cavity wall.
Keywords :
cavity resonators; gyrotrons; millimetre wave tubes; waveguide components; 140 GHz; 95 GHz; EHF; MM-wave gyrotrons; coupled cavities; coupling holes; fine electroformed screen; free space Gaussian beam; fundamental TE/sub 1,1/ input mode; gyrotron cavity modes excitation; high order rotating gyrotron modes; intermediate TE/sub 1,n/ cavity; iris; mode generators; quasi-optical mode converters; resonant cavity; translucent cavity wall; waveguide wall; Coaxial components; Eigenvalues and eigenfunctions; Frequency; Gyrotrons; Millimeter wave measurements; Optical waveguides; Q factor; Resonance; Rotation measurement; Tellurium;
Conference_Titel :
Infrared and Millimeter Waves, 2000. Conference Digest. 2000 25th International Conference on
Conference_Location :
Beijing, China
Print_ISBN :
0-7803-6513-5
DOI :
10.1109/ICIMW.2000.893028