An estimation method for the n port S parameters with n-1 port measurements

An estimation method of the n-port S-parameters for reciprocal circuits is presented. In this method, several known loads are connected to one port in turn and reflection and transmission characteristics among the remaining ports are measured. Therefore, there is no need to connect a network analyzer to the port that is connected to the known loads. S-parameters are obtained by solving a linear least-squares equation and a quadratic equation only. In addition, applying this method to estimate the S-parameters of an immunity test system, validness of this method is confirmed.