Behavioral level modeling of power amplifiers with varying antenna load

This paper presents an approach for behavioral level power amplifier modeling with varying antenna load. The derived model is based on device large signal S-parameter measurements of a commercially available W-CDMA power amplifier. A pulsed RF measurement setup, ensuring minimal device self-heating and providing variable complex load impedance, is described in detail. The use of polar and Cartesian representation of the power amplifier load impedance is discussed in terms of model complexity. The model validity is verified by comparing measured and simulate adjacent channel power ratios (ACPR). The measured and simulated ACPR show very good agreement and match at the nominal power amplifier drive level to within 2 dB over the maximum output VSWR ratings.