Work being conducted into increasing the efficiency of RF power generation, if described completely, could fill a large book. Efforts are underway not only in the areas discussed in this article, but in the use of different classes of amplifiers and assorted techniques that are combined to produce interesting results. Regardless of how these advances are achieved, one certainty is that the search for higher and higher efficiency will continue for as long as there is demand for ever higher data rates. By Barry Manz