Theory, Simulations, and Experiments of the Dispersion and Interaction Impedance for the Double-Slot Coupled-Cavity Slow Wave Structure in TWT

In this paper, a theoretical model is presented for the double-slot coupled-cavity slow wave structure (CCSWS). By matching boundary conditions in conjunction with Green´s function technique and moment method, the formulas for discussing the high frequency characteristics of the SWS, including dispersion and interaction impedance, are given. This model is validated by comparing its results of two typical double-slot CCSWS operating in X-band, one with inline slots and the other with staggered slots, with those obtained by computer simulation using Ansoft HFSS code. Comparison is also made with the experimental data as well as the equivalent circuit model of a particular double-slot CCSWS. The results show that the theoretical method strikes a better balance between the accuracy and the calculation efficiency than other methods.