Advances in Analog and RF IC Design for Wireless Communication Systems
This chapter presents high-efficiency power amplifiers (PAs) for wireless infrastructure. It starts by stating the importance of high efficiency and the historical evolution in base station PA concepts. It then introduces the current solution, the Doherty PA. After explaining the fundamentals of the Doherty PA, a novel implementation achieving more than 35% drain efficiency across a 6dB power back-off range and up to 20W peak power between 1.7 and 2.3GHz is given. Afterwards, a future PA concept, switch-mode outphasing PA, is introduced. Theory and implementation details of a class-E outphasing PA achieving more than 60% drain efficiency across a 6dB power back-off range and up to 19W peak power between 1800 and 2050MHz is explained. By the end of the chapter, an essential part of switch-mode PAs, high voltage (up to 10V) and high frequency (up to 4GHz) drivers are presented.