A HYBRID GAUSS-NEWTON-SIMULATED ANNEALING OPTIMIZER FOR EXTRACTION OFMESFET EQUIVALENT-CIRCUIT ELEMENTS

A new optimizer is presented for the extraction of the small-signal eq uivalent circuit elements (X underbar) of a GaAs FET from its measured scattering (S) parameters. The approach is a combination of the dampe d Gauss-Newton method, for the least-squares fitting of the S paramete rs, and the random search generalized simulated annealing (GSA). Novel features of the proposed approach include (i) an improved Kondoh step -by-step optimization of the objective functions grouped according to their sensitivity to variation of key equivalent circuit parameters (X underbar), and (ii) exploitation of the advantages derived from a tra nsformation of the objective functions from scattering parameters to i mpedance parameters.