Antiresonance in the retrieved material parameters of periodic and aperiodic composite materials

We study the occurrence of the so-called antiresonance in the material parameters (permittivity, permeability) characterizing the electromagnetic response of a composite material slab. The material parameters are retrieved using the wellknown reflection/transmission method. As many previous works have either claimed or assumed that the antiresonance is an effect caused by the periodicity of the composite material, we study in this work both periodic and aperiodic material samples.