Cold Test Validation of Metamaterial Based Rectangular Slow Wave Structure for High-Power Backward-Wave Oscillators


Eser D., DEMİR Ş.

2019 IEEE Pulsed Power and Plasma Science, PPPS 2019, Florida, United States Of America, 23 - 29 June 2019, vol.2019-June identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 2019-June
  • Doi Number: 10.1109/ppps34859.2019.9009803
  • City: Florida
  • Country: United States Of America
  • Keywords: Backward-wave oscillator (BWO), Dispersion Diagram, Interaction Impedance, Metamaterial, Reversed Cherenkov Radiation, Slow wave structure (SWS)
  • Middle East Technical University Affiliated: Yes

Abstract

© 2019 IEEE.In this paper, a novel S band metamaterial based rectangular slow-wave structure (RSWS) is proposed for high-power backward-wave oscillator (BWO). The circular waveguide is loaded with R-SWS that shows negative permittivity and permeability. Since RSWS shows negative permittivity and permeability which is the key characteristics of metamaterial, it can operate below the cut-off frequency. CST Studio Suite is used to analyze high frequency characteristic of SWS. Dispersion diagram of the unit cell is observed with Eigen Mode Solver which is dedicated to simulation of closed resonant structures. Interaction impedance of the unit cell is also observed. Since the beam-wave interaction occurs with TM mode, axial and absolute electric field are observed in simulation. Slow wave structure composed of 8 unit cell is fabricated and measured in network analyzer. Cold-Test measurement validates the TM mode propagation of RSWS. BWO based on this RSWS is shown to operate at 2.49 GHz with 23.8 % peak efficiency for 2 T magnetic field by using CST Particle Studio.