Development Overview of Sequential Power Amplifiers

Higher order modulation is widely used in modern Communication systems such as OFDM and CA which lead to high peak to average power ratio (PAPR). It's crucial for radio frequency (RF) power amplifiers (PAs) to maintain high efficiency not only at saturation, but also output power back-off working condition. Sequential Power Amplifier (SPA) is a technique proposed in recent years to reach these demands. Based on academic researches, the development of broadband high-efficiency SPA is reviewed. Finally, the developing trend of SPA is presented.