Plasma and Fusion Research

Volume 11, 2406085 (2016)

Regular Articles

Experimental Study on W-Band (75 - 110 GHz) Oversized Surface Wave Oscillator Driven by Weakly Relativistic Electron Beams
Min Thu SAN, Kazuo OGURA, Kiyoyuki YAMBE, Yuta ANNAKA, Shaoyan GONG, Jun KAWAMURA, Takuro MIURA, Shin KUBO1), Takashi SHIMOZUMA1), Sakuji KOBAYASHI1) and Kohji OKADA1)
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 27 November 2015 / Accepted 2 April 2016 / Published 10 June 2016)

Abstract

A W-band (75 - 110 GHz) oversized surface wave oscillator driven by weakly relativistic electron beams with energy in the range of 10 - 80 keV is studied. Rectangular corrugations are used as slow-wave structures (SWS) having surface waves with an upper cutoff frequency of approximately 100 GHz (W-band). Uniformly distributed annular electron beams are generated by a disk-type cold cathode and then are injected into the W-band oscillator. A longer SWS length causes the oscillator to function in both backward wave oscillator (BWO) and travelling wave tube (TWT) operations, and no meaningful oscillation occurs at the π-point or the Bragg condition. When the SWS length is short enough, oscillation occurs in all regions: BWO, π-point and TWT. The operations of the oscillator are strongly affected by the structure length. The maximum radiation power is estimated to be approximately 20 kW with the figure of merit of about 2 × 102 MW.GHz2.

Keywords

surface wave, travelling wave tube operation, backward wave oscillator operation, π-point, W-band

DOI: 10.1585/pfr.11.2406085

Full Text

PDF format (1.5Mbytes) PDF Download

References

  • [1] S.P. Bugaev et al., IEEE Trans. Plasma Sci. 18, 518 (1990).
  • [2] S.P. Bugaev et al., IEEE Trans. Plasma Sci. 18, 525 (1990).
  • [3] A.N. Vlasov et al., IEEE Trans. Plasma Sci. 28, 550 (2000).
  • [4] K. Ogura et al., IEEJ Trans. FM 125, 733 (2005).
  • [5] S. Aoyama et al., Trans Fusion Sci. Technol. 51, 325 (2007).
  • [6] K. Ogura et al., IEEJ Trans. FM 127, 681 (2007).
  • [7] S. Magori et al., Plasma Fusion Res. 9, 3406032 (2014).
  • [8] S. Gong et al., IEEE Trans. Plasma Sci. 43, 3530 (2015).
  • [9] H. Oe et al., J. Plasma Fusion Res. SERIES 8, 1477 (2009).
  • [10] K. Yambe et al., IEEE Trans. Plasma Sci. 41, 2781 (2013).
  • [11] H.L. Andrews et al., Phys. Rev. ST Accel. Beams 8, 050703 (2005).
  • [12] D.M. Pozar, Microwave Engineering, 4th ed. New York, NY, USA: Wiley, (2012), p. 720.
  • [13] Y. Takashima et al., J. Plasma Fusion Res. SERIES 8, 1512 (2009).
  • [14] K. Ogura et al., IEEE Trans. Plasma Sci. 41, 2729 (2013).
  • [15] K. Ogura et al., Plasma Fusion Res. 9, 3406022 (2014).
  • [16] K. Mizuno et al., IEEE Trans. Electron Devices ED-20, 749 (1973).
  • [17] I.V. Konoplev et al., Phys. Rev. E 76, 056406 (2007).