An Analytical Approach to LINC Power Combining Efficiency Estimation and Optimization

A new approach for studying the combiner efficiency in a LINC amplifier based on analytical expressions of the instantaneous combiner efficiency and the signal's probability distribution function (PDF) is proposed. The analytical expressions, derived for both a matched combiner and a Chirex outphasing combiner, are applied to compute the combiner efficiency of a LINC amplifier under CDMA and 64QAM signals. A direct approach to determining the optimal shunt reactance used in an outphasing combiner is also proposed and applied to both signals. Validation with a commercial simulator is given.