A Piecewise Sine Waveguide for Terahertz Traveling Wave Tube

Abstract

In this paper, a piecewise sine waveguide (PWSWG) is proposed as the slow-wave structure (SWS) to develop high power terahertz travelling wave tube (TWT). The PWSWG evolves from a rectangular waveguide oscillating with the piecewise sine curve along its longitudinal direction. Through the analysis of slow wave characteristics and transmission properties, it can be found that the PWSWG SWS has the advantages of high interaction impedance and excellent electromagnetic transmission performance. Furthermore, the calculation results of beam-wave interaction show that the TWT based on PWSWG SWS can generate the radiated power of 251W at the typical frequency of 220GHz, corresponding to a gain of 37.01dB and an interaction efficiency of 6.8%. Compared with the conventional sine waveguide (SWG) TWTs, the PWSWG TWT has higher interaction efficiency and shorter saturation tube length. In conclusion, the PWSWG will be considered as the potential SWS for high power terahertz radiation sources.