Analog Techniques for Efficiency Enhancement

Efficiency enhancement techniques based on load modulation of saturated power amplifiers (e.g., outphasing PAs) are well known for improving performance at back-off. Aside from the popular Doherty PA, however, conventional techniques require multiple modulated RF inputs, thereby complicating the digital baseband architecture. Furthermore, as carrier frequency and instantaneous bandwidths are scaled up for 5G systems, the nonlinear baseband computation required for most load modulation PAs exacerbates the bandwidth challenges. This presentation will examine these challenges and describe analog-domain techniques to reduce system complexity.