Vircator

An electrode, a cold cathode, at one end injects an intense electron beam, such as from a Marx generator or a flux compression generator, optionally with a suitable pulse forming network, e.g. a Blumlein transmission line.

The electrons are attracted to a thin anode, such as an aluminized PET film or a stainless steel mesh, that is connected to the grounded waveguide body.

The electron beam must be so intense as to exceed the space charge limiting current in that region, causing oscillations that generate microwaves.

The frequency, efficiency and other characteristics of the emitted beam depend on the precise physical configuration and operating parameters.

The rapidly accelerating and decelerating electrons, as they oscillate back and forth between the real and virtual cathode through the mesh anode at microwave frequencies, then produce electromagnetic radiation.