Scattering of chiral periodic structure

We propose, develop, and implement an exact method to analyze the scattering of chiral periodic structure. The method combines the building block approach of multimode network theory with a rigorous mode-matching procedure. Symmetry properties of the structure are employed to simplify the analysis. Numerical results are given to discuss physical properties of the structure. At low frequencies, when only two Floquet modes can propagate in chiral period layer, the scattering of plane waves by the chiral periodic structure acts approximately as the scattering of plane waves by a uniform chiral slab with parameters equal to the average of those for the periodic layer. At higher frequencies, we find anomalous coupling regions known as Wood´s anomalies and are explained by the excitation of and reradiation of leaky waveguide modes in the periodic layer.