Study of a power amplifier behavioral model with nonlinear thermal effects

In this communication, the modeling of electrothermal effects in power amplifiers with memory is explained through the formal deduction of a Volterra-based behavioral model. Starting with a circuit-level rationale, the dependence of amplifier nonlinearity on node voltages is extended with the introduction of a thermal voltage following a lowpass characteristic. A commercial amplifier has been extensively characterized at 2 GHz with WCDMA signals of different symbol rates, and the proposed model has been compared with other widely used approaches. This proposal obtains a better performance in terms of the NMSE, spectrum of the error signal, and number of coefficients, considering that the model is adjusted with only one set of parameters.