DC and RF breakdown analysis of a helix TWT

Ramagiri Santhosh Kumar, Ambrish Ghadiya, Shilpi Soni, and Dinesh Kumar Singh
Space Applications Centre,
Indian Space Research Organization, Ahmedabad-380 015, India
Dedicated to Prof B N Basu

Analysis of various breakdown mechanisms involved in a helix travelling-wave tube (TWT) was carried out using a commercially available software, CST Studio. The TWT mainly consists of electron gun, slow wave structure (SWS) and multi-stage depressed collector. These sub-assemblies were analyzed for DC, RF and thermal breakdown using different solver modules of the CST Studio. The electron gun and the collector assemblies were analyzed for DC breakdown for ambient pressure, vacuum and critical pressure. This analysis is required to assure the operation of the device at various test conditions in ambient pressure, at low pressure in thermo-vacuum chamber and during transition from ambient to vacuum, and as well during the development phase of the device. To avoid DC breakdown at critical pressure, the electrode interfaces were potted with DC 93500, an encapsulation material with high dielectric strength. The SWS was analyzed for multipaction and RF losses causing thermal breakdown. Both the electron gun and collector were found to have a minimum DC breakdown margin of 7.97 dB and the SWS had a minimum RF breakdown margin of 8.98 dB. © Anita Publications. All rights reserved.
Keywords: Multipaction, Corona, Triple-junction effect, Travelling wave tube (TWT)

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Method: Single- anonymous; Screened for Plagiarism? Yes
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