An electronic transmitter or receiver employing electromagnetic radiation as a coded signal carrier is described. In the transmitter, the electromagnetic radiation is emitted from ultra-small resonant structures when an electron beam passes proximate the structures. In the receiver, the electron beam passes near ultra-small resonant structures and is altered in path or velocity by the effect of the electromagnetic radiation on structures. The electron beam is accelerated to an appropriate current density without the use of a high power supply. Instead, a sequence of low power levels is supplied to a sequence of anodes in the electron beam path. The electron beam is thereby accelerated to a desired current density appropriate for the transmitter or receiver application without the need for a high-level power source.