A novel contra-wound slow-wave structure for travelling-wave tube amplifier

Backward-wave oscillation is frequently a problem in TWT amplifiers that use the conventional circular helix slow-wave structure (SWS). Circular contra-wound helix SWS, proposed in the past to solve this problem, is hard to fabricate at high frequencies. A planar version of the contra-wound structur...

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Main Author: Jha, Nilotpal
Other Authors: Sheel Aditya
Format: Final Year Project
Language:English
Published: 2014
Subjects:
Online Access:http://hdl.handle.net/10356/61445
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-614452023-07-07T16:42:38Z A novel contra-wound slow-wave structure for travelling-wave tube amplifier Jha, Nilotpal Sheel Aditya School of Electrical and Electronic Engineering DRNTU::Engineering Backward-wave oscillation is frequently a problem in TWT amplifiers that use the conventional circular helix slow-wave structure (SWS). Circular contra-wound helix SWS, proposed in the past to solve this problem, is hard to fabricate at high frequencies. A planar version of the contra-wound structure is easily realizable but has not been studied so far. This project involves design, fabrication and testing of a novel a planar contra-wound planar helix SWS that can be fabricated using printed circuit techniques. A simple PH-SEC structure has been modified into a contra-wound PH-SEC structure and benchmarked against previously simulated results to understand the dynamics of the CST software, requisite settings for running reliable simulations and the intricacies of CAD designing. The parameters studied include phase velocity, coupling impedance and S-parameters. It is shown with the help of simulated dispersion characteristics that the proposed structure decreases the risk of backward-wave oscillation in a TWT. The performance of the discussed structure has also been measured against that of a RRB-SEC structure designed earlier [14] and the new design proves to be an improvement over the latter in terms of having comparable S-parameters over a broader frequency range. The fabrication has been done using RO4003 substrate and annealed copper. The testing results fair reasonably well against the simulated results and have also been compared to the testing results for the RRB-SEC structure. The research work done towards this project has been selected for presentation at the European Microwave Conference 2014 to be held in Cecilia, Italy in October 2014. Bachelor of Engineering 2014-06-10T06:17:31Z 2014-06-10T06:17:31Z 2014 2014 Final Year Project (FYP) http://hdl.handle.net/10356/61445 en Nanyang Technological University 55 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering
spellingShingle DRNTU::Engineering
Jha, Nilotpal
A novel contra-wound slow-wave structure for travelling-wave tube amplifier
description Backward-wave oscillation is frequently a problem in TWT amplifiers that use the conventional circular helix slow-wave structure (SWS). Circular contra-wound helix SWS, proposed in the past to solve this problem, is hard to fabricate at high frequencies. A planar version of the contra-wound structure is easily realizable but has not been studied so far. This project involves design, fabrication and testing of a novel a planar contra-wound planar helix SWS that can be fabricated using printed circuit techniques. A simple PH-SEC structure has been modified into a contra-wound PH-SEC structure and benchmarked against previously simulated results to understand the dynamics of the CST software, requisite settings for running reliable simulations and the intricacies of CAD designing. The parameters studied include phase velocity, coupling impedance and S-parameters. It is shown with the help of simulated dispersion characteristics that the proposed structure decreases the risk of backward-wave oscillation in a TWT. The performance of the discussed structure has also been measured against that of a RRB-SEC structure designed earlier [14] and the new design proves to be an improvement over the latter in terms of having comparable S-parameters over a broader frequency range. The fabrication has been done using RO4003 substrate and annealed copper. The testing results fair reasonably well against the simulated results and have also been compared to the testing results for the RRB-SEC structure. The research work done towards this project has been selected for presentation at the European Microwave Conference 2014 to be held in Cecilia, Italy in October 2014.
author2 Sheel Aditya
author_facet Sheel Aditya
Jha, Nilotpal
format Final Year Project
author Jha, Nilotpal
author_sort Jha, Nilotpal
title A novel contra-wound slow-wave structure for travelling-wave tube amplifier
title_short A novel contra-wound slow-wave structure for travelling-wave tube amplifier
title_full A novel contra-wound slow-wave structure for travelling-wave tube amplifier
title_fullStr A novel contra-wound slow-wave structure for travelling-wave tube amplifier
title_full_unstemmed A novel contra-wound slow-wave structure for travelling-wave tube amplifier
title_sort novel contra-wound slow-wave structure for travelling-wave tube amplifier
publishDate 2014
url http://hdl.handle.net/10356/61445
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