Effects of Spatial Dispersion on Reflection from Mushroom-type Artificial Impedance Surfaces

TL;DR

This paper investigates how spatial dispersion affects reflection from mushroom-type artificial impedance surfaces and finds that under certain conditions, spatial dispersion effects can be nearly suppressed, allowing for simplified local modeling.

Contribution

It demonstrates that in thin wire medium slabs, spatial dispersion effects are minimal, enabling accurate local modeling of mushroom structures, which aids in designing artificial surfaces with plasmonic responses.

Findings

Spatial dispersion effects can be suppressed in thin wire medium slabs.

Local models accurately describe the reflection properties of mushroom structures.

Suppression of spatial dispersion simplifies the design of artificial surfaces.

Abstract

Several recent works have emphasized the role of spatial dispersion in wire media, and demonstrated that arrays of parallel metallic wires may behave very differently from a uniaxial local material with negative permittivity. Here, we investigate using local and non-local homogenization methods the effect of spatial dispersion on reflection from the mushroom structure introduced by Sievenpiper. The objective of the paper is to clarify the role of spatial dispersion in the mushroom structure and demonstrate that under some conditions it is suppressed. The metamaterial substrate, or metasurface, is modeled as a wire medium covered with an impedance surface. Surprisingly, it is found that in such configuration the effects of spatial dispersion may be nearly suppressed when the slab is electrically thin, and that the wire medium can be modeled very accurately using a local model. This result paves the way for the design of artificial surfaces that exploit the plasmonic-type response of the wire medium slab.