Two dimensional large signal analysis of helix traveling wave tube for non-ideal beam launching

In this paper, a two dimensional large signal analysis of helix traveling wave tube (TWT) is done for non-ideal beam launching. This actually means that the electrons enter the interaction region with an initial radial velocity. Focussing magnetic field is used in axial direction to confine the beam as it progresses down the interaction region. It is also shown that the TWT can sustain a radial velocity equal to 10 percent of the axial velocity for optimum tube performance so that the gain and efficiency characteristics are not much different from the ideal beam launching conditions.