Integrated Model for Design of SWS and Beam-Wave Interaction Analysis of a Planar THZ Sheet-Beam TWT

Abstract

A computationally efficient, integrated, and dynamic model has been developed for the design of a planar Slow Wave Structure (SWS) and beam-wave interaction analysis of a planar THz Traveling Wave Tube (TWT) with sheet beam. A Staggered Double Vane-Slow Wave Structure (SDV-SWS) is used for its numerous advantages over other types of SWSs. The integrated model determines RF performance of a planar TWT directly from the given beam voltage and center frequency by performing three different tasks, (i) determining geometrical parameters of an SDV-SWS of maximum possible bandwidth and high interaction impedance, (ii) determining RF circuit parameters of an SDV-SWS, and (iii) performing beam-wave interaction analysis of a planar TWT. The model was developed by adopting a numerically computing environment, MATLAB. Also, highly accurate numerical techniques with double precision were used, e.g., Sixth Order Runge Kutta Method was used for electron beam dynamic. The model was used to design and simulate a 0.22 THz Sheet Beam TWT of 100 W output power. The energy balance factor was achieved within ±0.001% over a very wide dynamic range from even 100 dB below saturation to more than 10 dB above saturation. The power growth of the forward wave achieves exactly 1 dB/dB. The program is fast enough for interactive use on a standard computer with a basic configuration. The model has been compared with the published works using a 3D electromagnetic field simulator for demonstrating its accuracy.