A Simplified Model for Chireix Outphasing Combiner Efficiency

In this paper, a simplified model for the instantaneous efficiency of the Chireix combiner is proposed. This model is given in the form of a very simple and intuitive expression that can replace the more complex expressions recently proposed in the literature. The model takes into account the impedance mismatch between the amplifiers and the lossless combining structure and is shown to be valid for all combiners considered. Validation of the simplified model is performed by comparison of the model´s predictions to experimental and simulation results for five different Chireix combiners. Excellent agreement between the proposed model, simulations and measurements is obtained in all cases considered