Study on Beam Wave Interaction of Terahertz Radiation Source Based on Grating Structure

The vacuum electron device (VED) is one of the best devices to generate terahertz wave with its advantages of high power, high frequency and power synthesis. In order to obtain higher power terahertz wave, it is imperative to improve the output power and efficiency of VED. For this aim, we propose a novel THz rectangular grating slow wave structure (SWS). The SWS can make full use of the longitudinal electric field of the slot, so that the electromagnetic wave can interact with the electron beam efficiently, so as to improve the beam-wave interaction efficiency and output power. The field characteristics of the novel SWS are analyzed, and the “cold” dispersion equations are derived by the eigen-function method, and the dispersion characteristics and coupling impedance are calculated. The results show that the grating SWS with double holes embed sheet beams has higher working frequency and coupling impedance than the ordinary grating without any slot. These studies provide theoretical guidance for the design of the grating SWS with double holes embed sheet beams.