Large-signal variability of microwave power amplifiers through efficient device sensitivity-based physical modeling

In the present article we present a comprehensive variability analysis of microwave power amplifiers in various operating classes by means of a recently developed numerically efficient technique for the physics-based variability analysis of devices operated in nonlinear conditions. Both a class A and a deep class AB power amplifier are considered, with the active device undergoing variations of main physical parameters such as doping, gate work function, and gate length. The results presented show for the first time that the physics-based variability analysis of nonlinear circuits is feasible and allows for a direct link between the PA performance uncertainty and the active device technological parameter variations. Both deterministic and statistical variations are taken into account, showing that the approach of Donati Guerrieri et al. (2016) allows for an aggressive reduction in computation time with respect to the variability analysis by means of conventional approaches, while retaining very good accuracy for parameter variations up to 10% of their nominal value. The highest sensitivity of the class A stage is found for the drain efficiency, while the class AB stage has a more involved behavior, with the highest sensitivity shifting from the drain efficiency to the output power as the input power increases.