Reflective Metasurfaces: Retrieval of Constitutive Effective Parameters Using Simplex S-Parameters

As a bridge linking propagating waves and surface waves, reflective metasurfaces play a significant role to manipulate electromagnetic (EM) waves. Without transmission coefficients, however, the effective constitutive parameters (epsilon(eff), mu(eff), eta(eff), z(eff)) of reflective metasurfaces cannot be retrieved by conventional theory. In this work, an innovative method using single S-parameters (only S-11) is proposed to retrieve the effective EM parameters for reflective metasurfaces. The validity of the method is demonstrated by imping TE-polarized EM waves normally and obliquely on the single- and multiple-layer unit cells. The retrieved results match well with each other corresponding to the assumption of passive homogeneous mediums. This method is beneficial for the design of reflective metasurfaces and other applications of anomalous reflection.