PROJECT TITLE :

Five-Wave Equation for Small-Signal Analysis of Traveling-Wave Tubes Considering the Effects of Axial Periodicity of the Interaction Structure

ABSTRACT:

The standard Pierce theory is used to research traveling-wave tube (TWT) amplifiers. This theory is a convenient technique to design helix TWTs. However, in some cases like coupled-cavity TWTs and folded-waveguide TWTs, this approach yields nonphysical results. In truth, backward-wave excitation may not be ignored for top-power wideband coupled cavities also for devices operating near the band edges. The Pierce-kind equation is changed to include each back plus forth RF waves simultaneously. A fifth-order algebraic equation comes that yields TWT little-signal gain in approximately the entire frequency band, together with close to cutoff frequencies. This approach is based on the coupling between 2 fast and slow space-charge waves and 3 RF house-harmonic waves, using independent house-harmonic approximation. The obtained equation could be used to research the coupled-cavity folded waveguide and ladder TWT structures.