Surface Susceptibilities as Compact Full-Wave Simulation Models of Fully-Reflective Volumetric Metasurfaces

TL;DR

This paper demonstrates that surface susceptibilities can serve as efficient, accurate full-wave models for fully-reflective volumetric metasurfaces, enabling reduced computational cost in simulating complex electromagnetic structures.

Contribution

It shows that surface susceptibilities can accurately model fully-reflective metasurfaces, including electrically isolated surfaces, and can be used as compact models in various simulation methods.

Findings

Surface susceptibilities accurately predict fields from fully-reflective metasurfaces.

The susceptibilities can model electrically isolated surfaces like PEC with dielectric cover.

Compact susceptibility models are effective in integral equation-based simulations.

Abstract

While metasurfaces (MSs) are constructed from deeply-subwavelength unit cells, they are generally electrically large and full-wave simulations of the complete structure are computationally expensive. Thus, to reduce this high computational cost, non-uniform MSs can be modelled as zero-thickness boundaries, with sheets of electric and magnetic polarizations related to the fields by surface susceptibilities and the generalized sheet transition conditions (GSTCs). While these two-sided boundary conditions have been extensively studied for single sheets of resonant particles, it has not been shown if they can correctly model structures where the two sides are electrically isolated, such as a fully-reflective surface. In particular, we consider in this work whether the fields scattered from a fully reflective metasurface can be correctly predicted for arbitrary field illuminations, with the source placed on either side of the surface. In the process, we also show the mapping of a PEC sheet with a dielectric cover layer to bi-anisotropic susceptibilities. Finally, we demonstrate the use of the susceptibilities as compact models for use in various simulation techniques, with an illustrative example of a parabolic reflector, for which the scattered fields are correctly computed using a integral equation (IE) based solver.