A Three-Port Nonlinear Dynamic Behavioral Model for Supply-Modulated RF PAs

We propose a three-port nonlinear dynamic behavioral model for supply-modulated power amplifiers (PAs). The proposed model not only accounts for the radio frequency (RF) input-output relationship, but also for the interaction between a modulated voltage supply, the RF output power and the supply current. The model is based on a modified Volterra formulation which accounts for the dynamic deviations with respect to a quasi-static model. The frequency-domain kernels of the proposed model are directly extracted from measurements performed with a low-frequency-extended large-signal network analyzer on an RF hand-set PA. The model is validated under random multitone modulated RF input and supply. The presented technique allows for the independent control of the RF and the supply ports. As such, it allows a separate description of both the dynamic contribution of the RF modulated input and of the dynamic supply voltage. The proposed model shows an improvement with respect to a quasi-static approach in predicting the RF output, the supply current, as well as the power-added efficiency.