A Frequency-Tunable [Formula Omitted]-Band Radial Relativistic Backward-Wave Oscillator

• Published in: IEEE transactions on plasma science 2019-01, Vol.47 (5), p.2562
• Main Authors: Yang, Fuxiang, Zhang, Xiaoping
• Format: Article
• Language: English
• Subjects: Drift tubes; Electron beams; Feasibility studies; High power microwaves; Microwaves; Plasma
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2019.2907534

In this paper, we propose a novel frequency-tunable [Formula Omitted]-band radial-line backward-wave oscillator (BWO). It operates in two high-order modes (i.e., TM02 or TM03 modes) so as to achieve a high power capacity, the reflector of which can effectively reduce the microwave leakage from the radial slow wave structure (SWS) to the diode region. The SWS is segmented into two sections, which can enhance the interaction between the electron beam and microwaves. The drift tube in between is capable of adjusting the operation frequency. In particle simulations, with the tube length of 6.1 mm, high-power microwaves with a frequency of 60.56 GHz are obtainable and the output power is 1.5 GW. The electron beam voltage is 524 kV and the beam current is 16.27 kA. By simply shrinking the tube to 3.9 mm, the operation frequency is tuned to 78.89 GHz and the microwave power yielded is 586.75 MW. This work validates the feasibility of tuning a radial-line BWO between two high-order modes, which will enlighten the design of other future frequency-tunable high-power microwave sources.