Phase velocity and interaction impedance on slow-wave structures for power traveling-wave tubes

In this work, some results from a theoretical cold analysis of the ring-bar slow-wave structure are shown. The ring-bar structure is suitable to be used in high-power traveling-wave tubes. Thus, an investigation was done in order to understand the properties of this structure and why it is better than single helices when a TWT is operated at high-voltage levels. The analytic model that best fits the ring-bar is the contra-wound helix that was used.