An Efficiency-Enhanced 0.5-THz BWO Using Double-Slot Embedded Electron Beams to Drive a Grating Loaded Rectangular Waveguide

The backward wave oscillator (BWO) is one of the best choices for generating high-power radiation waves in the terahertz (THz) region. In order to improve the efficiency of beam–wave interaction and output power, a novel THz BWO scheme is proposed in this article, which uses double-slot embedded electron beams (DSEEB) to drive a grating loaded rectangular waveguide (GLRW) slow wave structure (SWS). The dispersion relation and the coupling impedance of the proposed SWS are derived by using an eigenfunction method (EFM) and solved with a numerical method. The results show that the upper limit frequency and the coupling impedances are remarkably improved, which are greater than those of traditional grating SWS. Based on this scheme, a BWO operating at the frequency of 0.5 THz is designed. The particle-in-cell simulations show that the output power reaches 8.86 W with an efficiency of 0.9%, which is 2.5 times the electronic efficiency of the conventional BWO. Thus, the proposed scheme provides a promising aim to develop the high-power THz source, which may be used in THz biomedical and material studies, and so on.