Maximum microwave conversion efficiency from a modulated intense relativistic electron beam

Abstract
We calculate the power transfer from an intense modulated electron beam to an external load. The simple model fully incorporates various effects such as nonlinear beam loading, finite transit time, ac and dc space charges, and the beam’s initial velocity modulation. We show that a fully modulated beam may deliver up to a maximum of 57% of its power to a load without forming a virtual cathode.