DocumentCode :
2508023
Title :
Effects of end reflections on the performance of relativistic backward wave oscillators
Author :
Moreland, L.D. ; Schamiloglu, E. ; Lemke, R.W.
Author_Institution :
Dept. of Electr. & Comput. Eng., New Mexico Univ., Albuquerque, NM, USA
Volume :
1
fYear :
1995
fDate :
3-6 July 1995
Firstpage :
705
Abstract :
In a backward wave oscillator (BWO) the primary energy exchange occurs between the electron beam and the backward traveling wave within the slow wave structure (SWS). In most BWO configurations, the backward traveling wave is reflected by a cutoff neck at the entrance to the SWS and the radiation is extracted in the direction of the electron beam. Studies have investigated the effect of the forward traveling wave on the energy exchange between the electron bunches and the backward wave, and the effect of multiple end reflections and cavity resonances. In our experiments, we have observed changes in BWO performance as the phase of reflections at both ends of the SWS were changed. This was accomplished at the entrance of the SWS by placing a section of smooth-walled circular waveguide between the beginning of the SWS and the cutoff neck. At the exit of the SWS, smooth waveguide was added between the SWS and an additional reflection ring. The conversion efficiency from beam power to radiated power and the RF frequency were measured as a function of the length of smooth-walled waveguide introduced and is a measure of the influence of the forward wave on electron bunching as well as the cavity effects of the SWS due to end reflections. These results were compared with TWOQUICK computer simulations. These simulations included both cold tests of the electromagnetic response of the SWS configuration and comparisons of RF output. There is good overall agreement between the experimental results and numerical simulations.
Keywords :
backward wave oscillators; circular waveguides; digital simulation; electromagnetic wave reflection; electron beams; power conversion; power engineering computing; relativistic electron beam tubes; simulation; slow wave structures; RF frequency measurement; TWOQUICK computer simulations; additional reflection ring; backward traveling wave; backward wave; beam power; cavity effects; cavity resonances; conversion efficiency; cutoff neck; electromagnetic response; electron beam; electron bunches; electron bunching; end reflections; multiple end reflections; primary energy exchange; radiated power; relativistic backward wave oscillators; slow wave structure; smooth-walled circular waveguide; Electromagnetic waveguides; Electron beams; Energy exchange; Frequency measurement; Length measurement; Neck; Optical reflection; Oscillators; Power measurement; Radio frequency;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Pulsed Power Conference, 1995. Digest of Technical Papers., Tenth IEEE International
Conference_Location :
Albuquerque, NM, USA
Print_ISBN :
0-7803-2791-8
Type :
conf
DOI :
10.1109/PPC.1995.596798
Filename :
596798
Link To Document :
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