Quantification of power amplifiers´ static and dynamic distortions using frequency domain metrics

The quantification of power amplifiers´ distortions during the design stage is important in order to optimize their linearizability. For wideband signals such as LTE-Advanced, time domain characterization of power amplifiers requires specialized and costly measurement equipments. This paper proposes an approach for characterizing the distortions of power amplifiers based on frequency domain metrics. Accordingly, power amplifiers´ static as well as dynamic distortions are quantified using the adjacent channel leakage ratio and the spectrum asymmetry index, respectively. Both metrics are defined in the frequency domain and can be extracted from the measured spectrum at the amplifier´s output. The proposed metrics were applied for the characterization of two Doherty power amplifiers prototypes. The experimental results demonstrate the effectiveness and robustness of the proposed approach in comparing the strength of static distortions and memory effects of power amplifiers prototypes.