Accelerators used for nuclear-physics research require megawatts of radio-frequency energy- They currently employ vacuum-tube power amplifiers or conventional solid-state amplifiers that are inefficient and therefore consume a great deal of prime power- Many other applications including semiconductor processing, cellular-telephone base station transmitters, and military communication systems similarly use inefficient power amplifiers and therefore consume large amounts of electrical power-High-efficiency power-amplifier systems have been developed- However, an impediment to their adoption is their relatively high cost- The goals of high efficiency, wide bandwidth, linearity, and low cost will be achieved by optimizing and combining a number of techniques and devices- They include state-of-the-art transistors, high-efficiency amplification techniques, amplitude-modulation techniques, power combiners, signal processing, and controls-
