Mathematical model with minimum number of independent coefficients for transistors for high frequencies

A stepwise procedure is described to select the independent coefficients when forming a mathematical model of transistors for high frequencies. The basic idea is to determine the least-squares estimates of the coefficients from the measured scattering parameters S in a group of transistors of the same type. Examination of the correlation matrix of these estimates enables one to accept, in turn, the independent coefficient that has no linear relationship with the preceding ones already selected as independent.