The Doherty power amplifier

In this article, we show that the Doherty amplifier is capable of delivering the stringent requirements of the base station power amplifiers. We explain the operation principles, including both linearity and efficiency improvements, and the basic circuit configuration of the amplifier. Advanced design methods to operate across wide bandwidth and improve the linearity are also described. For verification, the Doherty amplifier is implemented using laterally diffused metal oxide semiconductor (LDMOS) transistors and measured using a WCDMA 4FA signal. These results show that the Doherty amplifier is a promising candidate for base station power amplifiers with wide bandwidth, high efficiency, and linearity