Design of a Broadband Planar RF Structure for a 0.22 THz Travelling Wave Tube

摘要

Planar broadband THz travelling wave tube is being designed for ultra broadband high speed data rate communication and imaging. A simplified analytical approach is developed for designing of a planar staggered double vane rectangular waveguide slow-wave structure (SDVSWS) for a broadband 0.22 THz 100W TWT. The structure is inherently compatible for sheet beam operation, and it is designed for an electron beam of voltage 20 kV and current 50 mA. 3D e.m. field simulator code CST-MWS was used for simulating the SDVSWS using the analytical design parameters. It is found that the dispersion characteristic by the analytical method matches well within 5% with the simulated dispersion characteristic of the structure. Effects of various parameters of a double-vane SWS on dispersion and impedance characteristics are evaluated for achieving a planar TWT of bandwidth more than 40 GHz with high gain. It is shown that pitch and vane height are most significant parameters and half-period staggering of double vanes in the structure provides wider bandwidth, high impedance and high symmetric RF electric field for efficient beam-wave interaction.