Index-near-zero properties of metallic meander structures

Vertical meanders composed of a continuous metallic film with rectangular profiles are promising for realizing frequency and spatial filtering functions due to the efficient electromagnetic coupling properties. This paper investigates numerically the band structures and transmission spectra of the meanders under variation of structural parameters as periodicity P and corrugation depth T. The numerical analysis is based on the S-matrix approach implemented with adaptive spatial resolution and factorization rules to optimize the calculation time and convergence. As metal Ag is chosen and the metal dispersion is described by a Drude model. Thin metallic meander slabs allow for the coupling of the surface plasmon polaritons (SPPs) which result in the known long range (LR) and short range (SR) SPPs due to the symmetrical and antisymmetrical charge distribution between the surfaces of the thin metallic films. The LRSPP and SRSPP modes depend on the structural parameters differently and therefore influence the optical functions of the structure differently. A transmission line equivalent circuit model is used to gain more insight in the relationship between the geometrical structure and electromagnetic response.