Experimental Investigation of a Shape-Optimized Staggered Double-Vane Slow-Wave Structure for Terahertz Traveling-Wave Tubes

Enormous concerns focus on the high-power and wide bandwidth traveling-wave tube (TWT) for its outstanding performance. In this article, a shape-optimized staggered double-vane slow-wave structure (SWS) for terahertz (THz) sheet beam TWT is proposed. The shape-optimized staggered double-vane SWS takes the advantages of higher interaction impedance, lower transmission loss, and lower phase velocity than conventional staggered double-vane SWSs. The shape-optimized staggered double-vane SWS with 85 periods is designed, fabricated, and cold tested. The measured transmission loss of the shape-optimized staggered double-vane SWS is less than 0.79 dB/cm in the frequency range of 0.211-0.26 THz, which is in good agreement with the simulation results. Furthermore, the beam-wave interaction analysis of a sheet beam TWT with this SWS is given. The output power is predicted to be >100 W with 3-dB bandwidth of >50 GHz. The results show that the shape-optimized staggered double-vane SWS is a very promising scheme to construct a high-power and wideband THz TWT for future applications such as communication and imaging.