A semi-physical power amplifier behavioral model capable of predicting gain expansion effects

A novel semi-physical power amplifier (PA) behavioral model (BM) that describes the input-output characteristic of PAs exhibiting gain expansion (GE) is introduced. The accurate prediction of GE is of particular importance because GE typically improves the power added efficiency (PAE) at high input powers. Though, GE impacts the spectral regrowth. Therefore, BMs that are capable of predicting GE, like the one introduced in this work, are highly desirable. In a case study, the proposed model is employed to predict the AM-AM distortions of a GaAs class AB PA designed for LTE applications. Excellent agreement between measurement and simulation results is obtained. The computational efficient model allows system-level simulations of advanced transmitter systems in order to optimize their modes of operation.