A simple envelope model for nonlinear power amplifiers with memory effects based on volterra expansion

For wideband communication systems, memory effects in power amplifiers (PAs) always become significant, which commonly make intermodulation-distortions (IMDs) response asymmetric in a two-tone test. The Volterra series is a general method to analyze and model the nonlinear PAs with the memory effects, while the complexity in the large number parameters to be calculated is a major limitation. In this paper, we propose a simple envelope from the Volterra series to represent the nonlinearity and the memory effects in the PAs. The proposed model reduces the parameters number remarkably and can express the asymmetric IMDs easily. The simulation results show that the proposed PA model is efficient to represent the nonlinear PA behaviors considering the memory effects.