Study on wideband THz backward wave oscillator driven by pseudospark-sourced sheet electron beam

Zhang, Jin and Zhang, Tianzhong and Alfadhl, Yasir and Chen, Xiaodong and Zhang, Liang and Yin, Huabi and Cross, Adrian W. (2020) Study on wideband THz backward wave oscillator driven by pseudospark-sourced sheet electron beam. IEEE Transactions on Electron Devices, 67 (8). pp. 3395-3402. ISSN 0018-9383 (https://doi.org/10.1109/TED.2020.3005362)

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Abstract

A backward wave oscillator (BWO) based on a double-staggered grating (DSG) slow wave structure (SWS) is investigated as a high-power wideband terahertz (THz) source, driven by a sheet electron beam emitting from a pseudospark plasma cathode. First, the DSG SWS is optimized in simulation to have a suitable dispersion characteristic. Then, the BWO with a wideband output structure consisting of a tapered section of DSG and an L-shaped connector is modeled under an operating voltage of 24-38 kV and a current density of 2- 5\times 10 {{7}} A/m 2 (beam current of 1.5-3.8 A). A maximum power of 3.9 kW is obtained, and a wide bandwidth of over 38 GHz (343-381 GHz) is achieved. The impact of fabricating errors of the SWS on the performance of the BWO is analyzed in simulation. The effects of the plasma in the interaction space on the BWO performance are also analyzed, showing that the plasma causes an increase in the oscillation frequency by 1.0-1.2.