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 within a series of spiral-shaped anodes to an appropriate current density without the use of a high power supply. Instead, a sequence of low power levels is supplied to the 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.