Low-profile Aperiodic Metasurfaces for High-efficiency Achromatic Anomalous Reflection over a Wide Bandwidth

TL;DR

This paper introduces low-profile, aperiodic metasurfaces that achieve high-efficiency, broadband, achromatic anomalous reflection by leveraging near-field interactions, overcoming chromatic aberrations common in traditional designs.

Contribution

The authors develop a novel integral-equation framework that exploits near-field interactions to realize broadband achromatic anomalous reflection with simple, low-profile metasurfaces.

Findings

Achieved wideband achromatic anomalous reflection at 10GHz

Demonstrated high efficiency and low profile of the metasurfaces

Validated design through experimental measurements

Abstract

Metasurface anomalous reflectors can enhance future wireless communication systems due to their ability to redirect electromagnetic waves and establish metasurface-assisted communication links. However, metasurface reflectors typically suffer from chromatic aberrations with the reflected angle shifting as the frequency varies. Herein, we design achromatic metasurfaces for anomalous reflection by using an integral-equation framework that fully accounts for the frequency dispersion of the individual scatterers (unit cells). Rather than engineering the dispersion of each metasurface cell locally, we harness the emerging near-field interactions (evanescent waves) between the scatterers to realize anomalous reflection at a fixed angle over a wide frequency range. Three anomalous reflectors are designed and experimentally verified at 10GHz, demonstrating high performance metrics compared to traditional achromatic reflectors, while employing simple, low-profile unit cells. The presented results pave an effective way to realize achromatic wave functionalities, such as anomalous reflection, refraction or lensing, over a wide bandwidth with low-profile and highly efficient metasurfaces.