Hybrid surface waves in chiral loaded resistive metasurfaces

Abstract

A theoretical investigation has been carried out on the propagation of hybrid surface waves supported by a chiral loaded resistive metasurface. The canonical boundary-value problem approach is used in the analytical modeling of this problem. To simulate the resistive metasurface, an impedance boundary condition is applied at the chiral-resistive metasurface interface. The characteristics equation was solved numerically in the kernel for computing the unknown value of the propagation constant ($\beta$) against its respective frequency ($\omega$). The numerical results reveal that the chiral loaded resistive metasurface supports the upper and lower hybrid surface modes in the GHz range. The propagation bandgap between the upper and lower hybrid surface modes is highly sensitive to the chiral strength (ξ), and the propagation bandgap can be tuned with the variation of chirality. The surface wave characteristics i.e., the dispersion curve, effective mode index (${N}_{\mathrm{eff}}$), field profiles, and phase speeds (${v}_{p}$), have been computed numerically for both the upper and lower hybrid surface modes. The influence of chirality (ξ), thickness ($t$), permittivity of chiral medium (${\varepsilon }_{c}$), and the permittivity of resistive metasurface (${\varepsilon }_{r}$) on the resonance frequency, confinement, and phase speed of surface waves have been analyzed and their tunability has been discussed. The results’ validity has been checked under special conditions and the numerical results converge to the published results. The presented numerical results may have potential applications in chip chiral sensing, enantiomeric detection, biochemical sensing, metasurface designing, and near-field hybrid surface communication devices.