  We analyze single and multilayered metamaterials by modeling each layer as a
metasurface with effective surface electric and magnetic susceptibility derived
through a thin film approximation. Employing a transfer matrix method, these
metasurfaces can be assembled into multilayered metamaterials to realize
certain functionalities. We demonstrate numerically that this approach provides
an alternative interpretation of metamaterial-based perfect absorption, showing
that the underlying mechanism is a modified Fabry-Perot resonance. This method
provides a general approach applicable for decoupled or weakly coupled
multilayered metamaterials.
