Abstract: | The results of investigation on the possibility of a substantial extension of the operating-frequency band of a slow-wave structure of coupled-cavities-chain type are presented for the case of a small variation in the slowing factor of the phase velocity of a wave, including, in the case of convergence of the cavity and slot passbands. The investigation is performed with the use of regression models for electrodynamic characteristics of the slowing structure that are constructed on the basis of the results obtained by the impedance design of experiments. Variants of wideband chains of coupled cavities with differences in the phase-velocity slowing factor of ±3% and the operating width of the cavity passband of up to 35%, as well as structures with merging of the cavity and slot passbands and a resulting passband of up to 70% and a coupling impedance of 18–0.4 Ω, are obtained. |