Nonlinearity Modeling of Chireix Outphasing Power Combiner Under Amplitude Imbalance This work proposes a concise standalone model for Chireix power combiner. The model is based on the analysis of the nonlinear behaviour of a Chireix power combiner under amplitude imbalance. The generalised equations for input impedance of Chireix combiner branches excited by signals with different amplitudes have been derived. The results predicted by the model were validated using both commercial high frequency circuit simulations and experimentally measured results. As a result the proposed model serves two purposes. For one it can be used directly in a larger circuit simulation to predict the performance of an outphasing power amplifier. It can also be used as the basis for a linearization strategy for outphasing power amplifiers.

Power Amplifiers Load Modulation Techniques for 5G in GaNonSi Techonology A Doherty power amplifier (DPA) and a Chireix power amplifier for 5th Generation (5G) wireless applications are presented in this paper. The power amplifiers are integrated in OMMIC 100 nm GaNonSi process. In both amplifiers, the xcexbb4 TLine are replaced with lumpedelements to reduce its area. The DPA presents a P sat  of 34 dBm (u003e2.5 W), a peak PAE of 41 % and a 9.4 dB gain at 3.6 GHz. At 7 dB output backoff (OBO) it exhibits a 34.2 % PAE. On the other hand, the Chireix outphasing PA provides a P sat  of 32 dBm (u003e1.5 W), a peak PAE of 54.9%, a gain of 10.4 dB and a 25 % PAE at 7 dB OBO. The occupied area of the DPA and Chireix amplifiers are 3.26 mm2and 3.2 mm2, respectively, including pads.