Researchers at MIT are launching a revolution in RF amplification, with vacuum tubes.
MIT researchers are developing a radio frequency (RF) power amplifier based on a ribbon-beam vacuum electron device. The new amplifier combines a half-century-old technology-vacuum electron devices, or "vacuum tubes" in the old terminology-with a recent MIT breakthrough: an elliptical, or "ribbon," electron beam. A ribbon electron beam is much more efficient for RF amplification than the one-dimensional, pencil-like electron beam that conventional vacuum electron devices emit. A ribbon-beam vacuum electron device requires less energy than either conventional vacuum electron devices or the solid-state transistors that replaced them in many applications decades ago.