Efficiency enhancement techniques for high-power amplification systems are now mature technologies, with Doherty power amplifiers (PAs) being widely used in field-deployed wireless base stations. A typical Doherty PA consists of two parallel amplifiers (a carrier amplifier, biased in class-AB, and a peaking amplifier, biased in class-C), an input analog splitter, and a nonisolated output power combiner. The operation of the Doherty PA is based on an active load modulation mechanism, which allows the carrier and peaking amplifiers to operate into optimal load-impedance trajectories that vary according to the amplitude of the input signal. This, in principle, results in increasing the average efficiency of the Doherty PA without compromising its linearity.