S-parameters are the reflection and transmission coefficients between the incident and reflected waves (i.e. Recall that a linear network can be characterised by a set of simultaneous equations describing the waves, b1 and b2, exiting from each port in terms of incident waves, a1 and a2, The Smith Chart displays reflection coefficient in terms of constant normalised resistance and reactance circles. The Si9000 v7 and later allows graphical representation of s-parameters S 11 and S 21 via a Smith Chart, a widely used tool for graphic solution of transmission-line networks.
