Large-Period Multichannel Metagratings For Broad-Angle Absorption

TL;DR

This paper introduces large-period multichannel metagratings that achieve broad-angle absorption by engineering mutual coupling among scatterers, offering a practical and efficient solution for applications like radar reduction and energy harvesting.

Contribution

It extends metagrating concepts to large periods, enabling multifunctional, wide-angle absorption with relaxed fabrication requirements.

Findings

High absorption across wide angular range

Effective mitigation of spurious scattering

Semianalytic design with standard PCB technology

Abstract

We present an alternative scheme for obtaining effective power dissipation in planar composites, extending the recently proposed concept of metagrating (MGs), sparse arrangements of polarizable particles (meta-atoms), to realize multifunctional absorbers. In contrast to typical metasurface solutions, where periodicities are limited to half of a wavelength at most to avoid high-order Floquet-Bloch modes, we purposely consider large-period MGs, relying on their proven ability to effectively mitigate spurious scattering. The absorption process is thus implemented via precise engineering of the mutual coupling between numerous individual scatterers fitting in the enlarged period, with these additional degrees of freedom further utilized to enforce the perfect absorption conditions for multiple excitation angles simultaneously. The resultant devices, utilizing a standard printed circuit board configuration obtained semianalytically while featuring relaxed fabrication demands, exhibit high absorption across a wide angular range, useful for radar cross section reduction and energy harvesting applications.