Optimization of the signal growth rate in a class of multicavity RKOs with axially varying geometry using a parallel real-valued evolutionary algorithm

Summary form only given. The relativistic klystron oscillator (RKO) is a high power microwave (HPM) source based on enhancing mature non-relativistic klystron technology, in which the kinetic energy of a population of electrons is converted into coherent microwave radiation. There is significant interest in maximizing the growth rate of the RKO´s microwave signal as a function of the RKO design parameters. This research investigates a class of multi-cavity RKOs with n/spl ges/2 cavities and n-1 drift regions. Cavities may have distinct natural frequencies, qualities, and impedances. Drift regions may have distinct radii, lengths, and loss coefficients, and consequently may have distinct stop currents. A small-signal, modal, steady-state model relates the signal growth rate to the beam parameters (voltage, current, and radius) and the waveguide parameters just mentioned. The model, which assumes weak cavity coupling and a cutoff waveguide, considers the effects of cavity resonances, electromagnetic coupling, and beam coupling. The growth rate is optimized using a parallel real-valued evolutionary algorithm (EA), which performs mutation, recombination, and selection on a population of candidate design parameters.