dr jian,how i get s parameter from plane wave

Hi, abdoeng:

S-parameters are defined based upon incident wave and reflected wave. For a general scattering problem, there is an incident planewave. However, there is not reflected wave. Instead there is scattered field and RCS is defined based upon scattered field and incident field. For FSS type of problem, we can consider scattered field as reflected field. In some sense, we should try to extract the reflected field from scattered field for periodical structures. However, we have not implemented this extraction. Regards.