Modelling and Measurement Results for RF Power amplifiers characterization with Memory effects

Abstract

In this paper, the experimental and the modelling investigation of nonlinear RF power amplifier are presented. A cross-covariance calculation was firstly being applied to the raw signals sampled at the Device Under Test (DUT) input and output to cancel the time delay. The behavioural polynomial model used to assess the system identification is characterized by the Normalized Mean Square Error (NMSE). These measurements are performed on a GaAs MESFET power transistor operating in class AB, driven by QPSK signal at 1575MHz. To accurately identify the memory effects, a time delay estimation study based on cross-covariance and Lagrange interpolation, was used to align the input and output raw baseband data. The results show a good agreement between measurement, conventional polynomial model, and the orthogonal polynomial model.