Prediction of Spectral Regrowth of Quasi-Memoryless Fifth-order RF Amplifiers under Multitone Excitation

New formulas for estimating the spectral regrowth at the output of RF Power Amplifiers (RFPAs) have been proposed. The formulas predict the average output power spectral density (PSD) of fifth-order quasi- memoryless RFPAs, excited with uncorrelated tones. The efficiency of the proposed approach is demonstrated by predicting the spectral regrowth in a commercial RFPA for different input power levels. The obtained results were compared to those of a harmonic balance simulation and have shown a good accuracy and time efficiency.