A crossed-field amplifier using a distributed field emission cathode

We propose to use an addressable array of emitters to provide a distributed electron source for use in a crossed-field amplifier (CFA). In our approach the dynamic control of the microwave device is obtained by using feedback from an array of device inputs and outputs to control the electron current density versus position within the device. The feedback consists of measurements of the RF output (noise, power) and of the collected current at the end of the device using a segmented collector while the inputs consist of the injected current into the device from an addressable array of cold cathode field emitters and the applied voltages to the emitters and cathode. The FEAs will be addressable so that the injection current into the device can be controlled spatially. This addressable approach should improve the performance of the device in terms of gain per length, efficiency, and possibly noise.