Ultra-Thin, Broad-Bandwidth FSS-Based Metamaterial Absorber with High Absorption Efficiency

Abstract

In this paper, we present a frequency selective surface (FSS)-based metamaterial absorber characterized by minimal thickness and broad bandwidth. The structures, with a total thickness of just 2 mm, were fabricated on an F4B substrate. Each repeating unit measured 20 mm × 20 mm. This absorber demonstrated an impressive absorption bandwidth of 5 GHz, covering the frequency range from 9.1 GHz to 14.5 GHz when an electromagnetic wave was incident perpendicularly. Notably, the absorptions of the material remained consistently above 90%, with the peak absorption reaching 100%. Extensive simulations were conducted to optimize the structural design, ensuring maximum efficiency. To elucidate the absorption mechanism, electromagnetic parameters such as ε_eff (effective permittivity) and μ_eff (effective permeability) were plotted. Additionally, current distribution images of both the top and bottom layers were analyzed to provide further insights into the absorption behavior and validate the theoretical models. The optimization process involved fine-tuning various parameters to achieve the desired absorption characteristics across a wide frequency range. These simulations helped in understanding the interaction between the electromagnetic waves and the absorber's structure, leading to the observed high absorption rates. Finally, the structure's effectiveness in absorbing vertically incident electromagnetic waves was verified through experimental testing. The experimental results corroborated the simulation findings, demonstrating the absorber's robustness and reliability in practical applications. This verification process included detailed measurements and analysis, ensuring the absorber's performance met the anticipated standards. Overall, the combination of minimal thickness, large bandwidth, and high absorption efficiency makes this FSS-based metamaterial absorber a significant advancement in the field. Its potential applications span various domains, including electromagnetic interference (EMI) shielding, stealth technology, and other areas requiring efficient absorption of electromagnetic waves. The successful experimental validation further emphasizes the practical utility of this innovative design