Load-pull circles analysis method for aplying the outphasing technique in power amplifier design

This paper presents a simple way of analyzing the suitability of a power amplifier for its use in an outphasing system. Simple steps are presented, allowing the designer to decide in advance if the outphasing technique will improve the efficiency versus back-off characteristic of the amplifier. For validating the method, an outphasing system for a Class AB amplifier has been designed, simulated and measured. In addition, a Class D amplifier has been also simulated to make a comparison of the results.