Julius Skudutis, Stanislovas Shtaras

Helical and meander super-wide-band structures are applied to communication equipment, measuring techniques, wide-band oscillographic traveling-wave tubes and other microwave devices.
Various models and methods are used for analysis of helical, meander and other types of slow-wave structures. The generalized theory of helical, meander and other types of slow-wave structures is based on the models consisting of the segments of multi-wire lines. However, there are some problems that are not solved yet.
Dielectric holders are necessary for helical and meander electrodes. These holders have influence on the properties of the structures, but this influence is not investigated comprehensively.
We have improved the model of meander structure with axial symmetry, have derived its dispersion equation, expression of input impedance and have estimated the influence of the dielectric holders of meander electrodes upon the electrical characteristics of meander slow-wave structures.
Slow-wave structures with constant moderation coefficient are necessary for the super-wide-band traveling-wave cathode-ray tubes and other microwave devices. According to the dispersion equation and frequency characteristics, stray capacitances between U-parts of meander electrode must be reduced in order to decrease the dispersion of phase velocity in the meander structure. Stray capacitances may be eliminated by using comb-shape dielectric holders for meander electrodes.