RF field is sensed to produce an incoming voltage that drives a microarray of electron guns in a sweep pattern towards a detector array. The electron guns emit a beam current that may amplify the incoming voltage signal, and the detector material may be selected to amplify the beam current at the detector, for example, by avalanche and/or cascade in a Schottky material, to provide a low current, high gain amplification. The microarrays may be arranged in various combinations to produce successive amplifications, frequency multipliers, transmit-receive amplifiers, crossbar switches, mixers, beamformers, and selective polarization devices, among other such devices.