The Analysis of a Dielectric-Loaded, Open Rectangular Waveguide Grating Slow-Wave Structure

The rectangular waveguide grating(RWG) slow wave structure(SWS) and its metamorphosis are potential high-frequency systems working in the millimeter or sub-millimeter wave band, with the merits of being easily made by micromachining, large transverse dimension and good heat dissipation. In this paper, the dispersion equation and the expression of interaction impendence of a dielectric-loaded, open rectangular waveguide grating SWS are derived, and the influence of dielectric-loading on the high frequency characteristic including the dispersion properties, interaction impedance and the longitudinal electric field of the structure are analyzed based on the numerical calculation. At present, the major trend of the development of traveling wave tube (TWT) is to get the wider bandwidth, higher power output, higher efficiency, better linearity, higher reliability and longer life. However, with the working frequency increasing higher, which requires the smaller size of the structure, the traditional ways of processing such small size become more and more difficult, unable to meet the accuracy. Thus, the micro-processing technology should be introduced. The rectangular waveguide grating SWS and its metamorphosis, which are suit for micromachining, maybe potential highfrequency systems for the high power vacuum devices working in the millimeter or sub-millimeter wave band. Periodic structures involving rectangular waveguide SWS have received much attention as classic SWS structures. The purpose of this paper is to investigate how the dispersion characteristics and the interaction impendence of the open rectangular waveguide SWS are affected by dielectric loading.