Crossed-Field Amplifiers: Theory of Operation

The CFA is a vacuum electron device (VED) which might best be described as part magnetron and part TWT (Traveling Wave Tube). It is like a magnetron because it utilizes the same type of electronic interaction that a magnetron does (crossed electric and magnetic fields) and it derives many of the magnetron's characteristics as a result. It is like a TWT because electronic interaction is with a traveling wave and, of course, it is an amplifier (In a magnetron the electronic interaction is with a standing wave.) Power can be generated with high efficiency for the same reasons that a magnetron can do so. Power is also generated at voltage levels similar to those of a magnetron. In fact many CFA's look quite like a magnetron with the same form factor but with the addition of an input port.