Investigation of X-parameters modeling for accurate envelope tracking power amplifier system simulations

This work reports the experimental evaluation of X-parameters models for the simulation of ET systems. We have extracted 2-port and 3-port X-parameters models from large signal vector measurements, for a GaAs PA with 40 dBm nominal peak power at 850 MHz. The data suggests that 3-port X-parameter model not only leads to an accuracy improvement during the estimation of average DE and ACLR but also permits the extraction of constant gain shaping functions that increase the overall system linearity.