High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

• Main Authors: Chiara Ramella, Anna Piacibello, Roberto Quaglia, Vittorio Camarchia, Marco Pirola
• Format: Article
• Language: English
• Published: MDPI AG 2017-11-01
• Series: Electronics
• Subjects: high power amplifiers; high frequency transmitters; wireless communications; high efficiency; Doherty power amplifier; Chireix outphasing amplifier; load modulated balanced amplifier
• Online Access: https://www.mdpi.com/2079-9292/6/4/96

Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed.