Impact of resonator geometry and its coupling with ground plane on ultrathin metamaterial perfect absorbers

TL;DR

This paper explores how the geometry of resonators and their coupling with the ground plane influence the performance of ultrathin metamaterial perfect absorbers, demonstrating that geometric modifications can reduce thickness and enhance absorption.

Contribution

It provides a detailed analysis of the effects of resonator geometry and near-field coupling on absorber performance, with validated theoretical and numerical models.

Findings

Resonator geometry modifications reduce absorber thickness.

Destructive interference explains near-unity absorption.

Near-field coupling significantly affects absorption performance.

Abstract

We investigate the impact of resonator geometry and its coupling with ground plane on the performance of metamaterial perfect absorbers. Using a cross-resonator as an example structure, we find that the absorber thickness can be further reduced through modifying the geometric dimensions of the resonators. Numerical simulations and theoretical calculations reveal that destructive interference of multiple reflections is responsible for the near-unity absorption. The near-field coupling between the resonator array and ground plane can be significant. When this coupling is taken into account, the theoretical results calculated using the interference model are in excellent agreement with experiments and numerical simulations.