Model of Helix Traveling Wave Tube Including the Slow-Wave Structure Dispersion Characteristics and Space-Charge Effect

An analytical model for the interaction between a linear electron beam and a realistic helix slow-wave structure (SWS) in a traveling wave tube (TWT) is provided. It is a generalization of the Pierce model for the interaction, assuming
$a$
one-dimensional electron flow along a dispersive helix SWS, with space-charge effects accounted for. The used phase velocity and characteristic impedance are extracted from full-wave simulations. The calculated gain versus frequency is compared with results from the 1D Lagrangian TWT code, LATTE.