Surface Impedance Modeling of All-Dielectric Metasurfaces

TL;DR

This paper presents an analytical model for all-dielectric metasurfaces that accurately predicts their electromagnetic response, facilitating design and understanding of advanced optical and microwave devices.

Contribution

The authors introduce a combined Mie theory and homogenization approach to derive closed-form surface impedance expressions for dielectric metasurfaces.

Findings

Model validated with full-wave simulations

Enables design of broadband optical mirrors and nanoantenna reflectarrays

Provides deeper understanding of scattering responses

Abstract

We develop a simple and reliable analytical model that allows describing the electromagnetic response of all-dielectric metasurfaces consisting of a single-layer array of high-permittivity spherical particles. By combining Mie theory with a bi-dimensional homogenization approach, we derive closed-form expressions of the electric and magnetic surface impedances exhibited by the metasurface and, thus, its reflection and transmission coefficients. The effectiveness of the proposed approach is validated through a set of full-wave simulations. The availability of the analytical model here developed allows a more in-depth understanding of the complex scattering response of these electromagnetic structures and enables the design of innovative devices operating throughout the whole electromagnetic spectrum, including, for example, unconventional reflectors for antennas, broadband optical mirrors, and highly efficient nanoantenna reflectarrays.