Development of a "smart" crossed-field amplifier

Abstract

Summary form only given. A "smart" crossed field amplifier (CFA) is being developed to look at the ability to control multiple inputs while monitoring diagnostic outputs and to adjust the amplifier operating parameters to improve device performance. The cathode will consist of spatially addressable arrays of gated field emitter arrays (FEAs)s which will be distributed across the CFA so that the current and current density can be injected into the interaction space as needed in order to provide optimum interaction with the RF circuit locally rather than globally. A number of diagnostics for measurement of the rf power, the injected beam current, and the end collected current (in two dimensions) will be used to provide feedback information to a control system. This control system will be used to adjust the device operation to achieve the optimal performance for a given set of conditions. The cathode structure and slow wave circuit will be fabricated using a low temperature co-fired ceramic (LTCC) and thick film metal electrodes. Slits will be machined in an LTCC plate with the FEAs place below the slits to allow injection of the electrons while protecting the FEAs. A thick film metal layer provides the cathode (or sole electrode) voltage. Floating DC to DC converters will be used to adjust the injected beam current from the field emission arrays. The 1 GHz CFA will have an output power of -250 W with an expected gain of 15 dB. Preliminary experimental results from the CFA will be presented. The experimental results will be compared with simulation results using the electron trajectory code Lorentz and the Air Force 3D electromagnetic simulation ICEPIC2.