Design of a wide-angle stable bendable dual-band metamaterial absorber in the GHz spectrum

A metamaterial-based ultra-thin dual-band absorber is designed in this work using three layers of materials (Copper - FR-4 - Copper) for microwave absorption in which the resonance band lies on 5.3GHz (C-band) and $13.4 \mathrm{GHz}(\mathrm{Ku}-$ band), with a bandwidth of 0.09GHz and 0.223GHz, respectively. The absorption levels are found to be $99.94 \%$ and $\mathbf{9 8. 4 \%}$, respectively. The design is numerically analyzed using the Finite Integration Technique. The structure is tested with different oblique incident angles and it provides reliable performance up to 60°. Mechanical bending analysis on the absorber performance is also done to check the reliability of the structure in harsh environments. The design is capable of showing good absorbance performance under different convex and concave mechanical bending. The field distribution of the structure is also investigated. The design can be used in $\mathbf{G H z}$ applications such as detecting the salinity of the soil, distinguishing vegetable oils from animal fat, detecting the saturation level of edible oils, and WLAN applications at the C band.