De-Embedding for Coupled Three-Port Devices

De-embedding techniques have been introduced to evaluate the real electrical performances of a device under test (DUT), e.g., the traditional thru-reflect-line and short-open-load-thru standards, where the transfer matrix (T-matrix) and its inverse form are adopted in the mathematical process. A DUT may have three coupled ports in the fields of radio frequency and electromagnetic compatibility. The symmetry in the corresponding S-matrix breaks down, because the numbers of incident and reflected ports are not equal. Thus, it leads to a nonsquare T-matrix by definition. Given that the inverse expression of a nonsquare matrix does not exist, the conventional de-embedding methods are inapplicable for a coupled three-port network. In this article, a de-embedding algorithm, which is feasible for coupled three-port devices, is proposed and verified through the measurement. The proposed de-embedding technique may also be applied on devices with more than three ports.