Multiport scattering matrix measurement with a two-port network analyzer using only virtual auxiliary terminations

Almost all methods for measuring the scattering matrix of a multiport device with a two-port vector network analyzer require fully characterizing auxiliary terminations, which could turn out to be a challenging task as the case may be. In this paper, a technique is described that measures auxiliary terminations indirectly. Hence, it relaxes the measurement of auxiliary terminations. In addition, the concept of virtual auxiliary terminations and the use of two-port network analyzer to measure a three- port directional coupler are verified by experimental results.