Investigation on Sheet Beam Folded V-Shape Groove Waveguide for Millimeter-Wave TWT

In this paper, a novel slow-wave structure (SWS) called folded V-shape groove waveguide SWS is proposed. The high frequency characteristics of this SWS is studied. An input and output waveguide transition structure, which is appropriate for this new kind of SWS is put forward. The transmission loss of the folded V-shape groove waveguide is lower than that of folded rectangular groove waveguide. The dimension of the folded V-shape groove waveguide is larger than that of the folded rectangular groove waveguide at the millimeter waveband, even at terahertz waveband. Based on this kind of SWS, a W-band sheet beam traveling-wave tube is studied, whose beam-wave interaction is calculated by means of the simulation software. The calculation results show that the output power can be over 260 W within 3-dB bandwidth from 84 to 98 GHz, the gain can reach up to 36 dB, and the electron efficiency is 12.33% at the center frequency.