An effective optimization for microwave power device modeling [GaAs MESFET]

A new systematic optimization strategy for extracting the model parameters of a small-signal equivalent circuit of a microwave power GaAs MESFET is proposed. On the basis of sensitivity analysis of error functions of the model elements, a rearrangement of the optimization sequence of sub-error functions referring to the model element sensitivities from large to small, and a transformation of optimization directions of error functions along with optimal directions, the global-error function is fast convergent under given starting values. In addition, the logarithmic damping algorithm is also proposed for stabilizing the final results by controlling the updates of insensitive model elements. The proposed approach is applied to extract the parameters of a microwave power GaAs MESFET chip with gate-width 2100 μm under different biases. The results show that the agreement is good between the calculated values and the MESFET measurement data.