Recirculating Planar Crossed-Field Amplifiers

Abstract

The Recirculating Planar Crossed-Field Amplifier (RPCFA) is an adaptation of the Recirculating Planar Magnetron (RPM) that has been the focus of research at the University of Michigan’s Plasma, Pulsed Power and Microwave Laboratory for nearly a decade. The RPM is a high power microwave (HPM) source that utilizes an innovative geometry to overcome some of the power generation limitations of existing magnetrons while maintaining the characteristic high efficiencies of these devices. The large planar cathode emits higher currents, leading to higher power, than a rod cathode at space charge limited densities due to its increased emitting surface area. The recirculating interaction space effectively recycles the electron beam, which preserves the electronic efficiency of the device. The RPCFA utilizes a geometry similar to the RPM and is likewise expected to hold the same advantages over traditional CFAs that the RPM holds over traditional magnetrons. Additionally, the planar amplifying structure permits the injection and extraction ports be placed physically far away from each other. This allows the Brillouin hub to demodulate over a long distance which minimizes feedback, a primary power limiting mechanism in cylindrical CFAs. The focus of this thesis is to design and test a prototype RPCFA which demonstrates these features.