THEORY AND SIMULATION OF A HIGH-POWER MICROWAVE CONVERTER FOR CURRENT-DENSITY-MODULATED, ANNULAR, RELATIVISTIC ELECTRON-BEAMS

The efficiency of converting the kinetic energy of a current-density-modulated, annular, relativistic electron beam into high-power microwaves depends on details of the beam, and the convertor geometry. The latter issue is investigated in this paper for a particular choice of convertor. Maxwell's equations are solved for the case in which a structure comprised of a cylindrical cavity coupled to a waveguide by an impedance transformer is excited by a symmetric, transverse magnetic wave. The field solutions are employed to determine the effect that the transformer/waveguide system has on the resonant properties of the cavity. An example is given in which the analytic model is used to obtain maximum power output in a numerical simulation.