Interaction Impedance of a Practical Helix Slow-Wave Structure using Tape Helix Model

Abstract

An expression for interaction impedance of a practical helix slow-wave structure used in a high power, broad-band Travelling Wave Tube, based on tape helix model is derived. The method is validated by comparing the theoretical values of axial propagation constant and the interaction impedance with the experimental data for typical structures.

Indexing terms:

• Slow-wave structure
• Travelling-wave tube
• Interaction impedance

Additional information

Notes on contributors

R K Gupta

R K Gupta was born in January 1955. He received the BSc Engg Degree and M Tech degree in Electronics & Microwave Electronics from Delhi University in 1976 and 1979, respectively.

He joined CEERI, Pilani, in March 1980. Since then he has been working on problems related to TWTs. During 1987–1989, he was a German Academic Exchange Service fellow in Germany where he worked at the Technical University of Hamburg-Harburg, Hamburg, and Institute of Technical Physics, Research Centre Karlsruhe, Karlsruhe, in mm-wave helix & coupled cavity TWTs and problems related to gyrotrons. He was on deputation to Department of Engineering, Lancaster University, UK during July-Oct 1992. He was given JC Bose Memorial award of IETE for the best paper on Engineering Application for the year 1992–93 on the paper “CAD of a Helix TWT”. AT present he is Chief-Investigator & Project Leader for the DLRL (DRDO) sponsored project “Design and Development of Gain & Phase Matched Mini Helix TWT”.

Mr R K Gupta is a life-fellow IETE, senior member CSI and life-member of IVS, IFTA, IPA, MRSI & MSI.

A K Sinha

A K Sinha was born in Bhabua (Bihar) in July 23, 1954. He received BSc (Hans), MSc and PhD degrees from Ranchi University, Ranchi in 1973, 1975 and 1986 respectively.

During 1977–1989 he served Regional Institute of Technology, Jamshedpur, and Jamshedpur Workers' College, Jamshedpur. Since June 1989, he has been working in CEERI, Pilani on design and development of microwave tubes. He published more than 50 research papers in reputed Indian and Foreign Journals and conference proceedings. He supervised many M Tech and PhD dissertations. He visited University of Lancaster (UK) as “Visiting Research Fellow”. His current areas of interest include broadbanding and modelling of TWTs, gyrotrons, rf windows, electron beam optics and microwave heating applicators.

Dr Sinha is Life members of IETE, IVS, IFTA, IPA & ISCA, India and Assoc. member of CSI, India.

S N Joshi

S N Joshi was born on October 15, 1946. He received the BSc and MSc (Tech) degrees from the University of Allahabad in 1964 and 1967, respectively.

For the last 30 years, he has been associated with the design and development of microware tubes at the Central Electronics Engineering Research Institute, Pilani. His past work includes research and development on high-power multicavity magnetrons and helix TWTs. He was Chairman of DoE's Review Committees on 'Dispenser Cathodes” and “Microwave Circuits” upto 1995. He was a member of DoE's NRC working Group upto 1994. He is a member of various review committees of DRDO, ISRO, BHU, IPR & SAMEER. He visited Department of Electronics, Lancaster University, UK during July-Aug 1991. He was given JC Bose Award for the best paper on Engineering Application for the year 1992–93 on the paper “CAD of a Helix TWT”. He chaired various Technical Sessions on Microwave Tubes in National & International Symposiums. He had coordinated the activities of entire MW Tubes Area of CEERI as its Area Coordinator during Feb 1990 to May 1994 and at present as a Group Leader of Communication Tubes Group, which comprised mainly projects on Broadband Mini Helix TWT, CC TWT from DRDO & Space TWT from ISRO.

He is a life-fellow of IETE and life-member of IVS, IFTA & IPA.