Power Amplifier Load‐Modulation Ratio

Abstract Load modulation is a technique to enhance the energy efficiency of power amplifiers for non‐constant envelope signals. These types of signals are very often used for wireless communication systems. Most cellular base stations today employ Doherty power amplifiers, which utilize load modulation as the underlying mechanism. The load‐modulation ratio quantifies how much the load impedance of a power amplifier varies during its operation. In principle, a higher load‐modulation ratio yields efficiency enhancement of a power amplifier at a lower‐power level from its peak capacity. In practice, this ratio needs to be designed carefully to optimize the performance of power amplifiers.