Impact of unit cell variation on visible spectrum multiband metamaterial absorbers

This study explores the design and parametric analysis of a dual-band metamaterial absorber optimized for the visible optical range. The absorber enhances tunability and efficiency across frequency bands by utilizing a periodic sub-wavelength unit cell. Comprising a metal-dielectric-metal structure with Silver layers and a magnesium fluoride dielectric, it operates in the $1-10 \mu \mathrm{m}$ wavelength range. The design’s effectiveness for dual-band infrared emission is analyzed using the finite element method in the frequency domain. The terahertz absorption peaks (89% and 65%) are detected, characterized by narrow line widths and significant absorption coefficients at discrete resonance frequencies ($1.54 \mu \mathrm{~m}$, and $6.1 \mu \mathrm{~m}$). Notably, the temperature-dependent variations in IR stealth capabilities are illustrated, achieving a remarkable reduction in infrared radiation signatures at 750K within specific atmospheric windows, exceeding 95.90% and 95.47%, without significant heat dissipation in the non-atmospheric window. Comprehensive parametric studies, varying patch structures to circular and triangular shapes with consistent dimensions, reveal the trade-offs between absorption bandwidth, efficiency, and spectral radiation. These findings provide key insights for developing advanced metamaterial absorbers with applications in electromagnetic stealth and thermal dissipation management.