Multi-port scattering matrix measurement using a reduced-port network analyzer

A novel method to acquire the scattering matrix of an n-port network from the measurements using a reduced-port network analyzer is developed. This method can obtain the scattering matrix of a nonreciprocal or reciprocal n-port network with the use of a three-port or two-port network analyzer. The formulation of this method considers the imperfection of terminators used in the measurement, and only two of the terminators are required to be known. Experimental results of a four-port microstrip circuit show the good accuracy using the developed method.