Asian Journal of Physics Vol 32, Nos 9 – 12 (2023) 473-478

Design of a simplified electron gun without BFE for linear beam tubes

Suneeta Arya, Atmakuru Nagaraju, and Sanjay Kumar Ghosh
Central Electronics Engineering Research Institute, CSIR, Pilani, Rajasthan- 333 031
Dedicated to Prof B N Basu

Design and realization of electron gun for high frequency helix traveling-wave tubes (TWTs) with enhanced current density remained a challenging task. In conventional multi-electrode electron gun geometry, both radial and axial positions of electrodes (namely, beam focus electrode (BFE) and various anodes) with respect to the cathode are the key parameters for controlling the electron beam optics. In particular, geometry and position of BFE with respect to the cathode are very complex and sensitive. To avoid such complexity, a simple electron gun, without BFE, has been designed and proposed in this paper. In the proposed design, the BFE has been replaced with a simple geometry anode, which plays important role in controlling beam optics and subsequent enhancement of the beam current. Proposed method eliminates the use of a BFE having complex geometry and also the complexity of maintaining its critical axial and radial distances with respect to the cathode. These two improvements make the electron gun assembly simple and straightforward. The proposed electron gun has been modelled in commercial simulation codes EGUN and CST Studio and compared against a practical conventional gun as a special case. © Anita Publications. All rights reserved.
Keywords: Traveling wave tube (TWT), Electron gun, Parametric analysis.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
Buy this Article in Print © Anita Publications. All rights reserve


  1. Mallon K P, TWTAs for Satellite communications: Past, present and future, Proc IEEE International Vacuum Electronics Conference, (2008)14–15; doi. 10.1109/IVELEC.2008.4556558.
  2. Chong C K, Menninger W L, Latest advancements in high-power millimeter-wave helix TWTs, IEEE Trans Plasma Sci, 38(2010)1227–1238.
  3. Luo J, Feng J, Gong Y, A Review of Microwave Vacuum Devices in China: Theory and Device Development Including High-Power Klystrons, Spaceborne TWTs, and Gyro-TWTs, IEEE Microw Mag, 22(2021)18–33.
  4. Basu B N, Electromagnetic Theory and Applications in Beam-Wave Electronics, World Scientific, 1996.
  5. Menninger W L, Benton R T, Choi M S, Feicht J R, Hallsten U R, Limburg H C, McGeary W L, Zhai X, 70% efficient Ku-band and C-band TWTs for satellite downlinks, IEEE Trans Electron Devices, 52(2005)673–678.
  6. Komm D S, Benton R T, Limburg H C, Menninger W L, Zhai X, Advances in space TWT efficiencies, IEEE Trans Electron Devices, 48(2001)174–176.
  7. Livreri P, Badalamenti R, Muratore A, Optimum Design and Performance of an Electron Gun for a Ka-Band TWT, IEEE Trans Electron Devices, 66(2019)4036–4041.
  8. Wei Y-X, Liu S-Q, Huang M-G, Li X-X, Liu J-Y, Du C-H, Liu P-K, Experiment for Evaluating a K-Band Space TWT Electron Beam, IEEE Trans Electron Devices, 68(2021)3596–3603.
  9. Sharma R K, Choudhury A R, Arya S, Ghosh S K, Srivastava V, Design and Experimental Evaluation of Dual-Anode Electron Gun and PPM Focusing of Helix TWT, IEEE Trans Electron Devices, 62(2015)3419–3425.
  10. Shankar A, Nagaraju A, Choudhury A R, Ghosh S K, Flexi Electrode Electron Gun for Long Life Travelling-Wave Tubes, Prog Electromagn Res Lett, 91(2020)117–122.
  11. Herrmannsfeldt W B, EGUN: An Electron Optics and Gun Design Program, SLAC, Stanford, CA, USA, 1988.
  12. CST Design Studio, 2018, user manual.
  13. Vaughan J R M, Synthesis of the Pierce gun, IEEE Trans Electron Devices, 28(1981)37–41.
  14. Dong X, Xianxia L, Mingguang H, Junting C, Measurement and analysis of dual anode electron gun for Ka-band Space TWT, 2016 IEEE International Vacuum Electronics Conference (IVEC), (2016), 1–2; doi. 10.1109/IVEC.2016.7561918.
  15. Wilson J D, Wintucky E G, Vaden K R, Force D A, Krainsky I L, Simons R N, Robbins N R, Menninger W L, Dibb D R, Lewis D E, Advances in Space Traveling-Wave Tubes for NASA Missions, Proc IEEE, 95(2007)1958–1967.
  16. Thorington C B, Computer simulation of ion trapping and detrapping in a PPM focused traveling wave tube, Abstracts. International Vacuum Electronics Conference 2000 (Cat No.00EX392), (2000) 2; doi: 10.1109/OVE:EC.2000.847539.