Design of microwave metamaterial absorber for Ku-, X-, and C- band applications

In the microwave domain, a compact, polarization- and angle-insensitive, ultrathin three-band metamaterial absorber (MMA) is designed, fabricated, and investigated in this article. The two copper layers are sandwiched between a FR4 substrate. In order to mitigate the term "perfect MMA," the proposed unit cell structure with patches achieves practically good absorption at the Ku, X, and C bands. The proposed absorber comprises a square, circular and octagon shape patches at the boundary. At the relevant frequencies of 15.29 GHz (Ku-band), 8.59 GHz (X-band), and 6.09 GHz (C-band), the structure offers 99.9 %, 85 %, and 95 % absorptivity. Along with its ultrathin form, the structure's size is on the order of 10 × 10 × 0.8 mm3. Patches in the boundary patterns of squares, circular, and octagonal are present in the suggested absorber. Transverse electric (TE) and transverse magnetic (TM) waves exhibit the same absorptivity. Plots of the electric field (E-field), magnetic field (M-field), and surface current distributions are used to study the structure's physical workings. The stability of the suggested design is further supported by the various incidence and polarisation angles. Finally, it is found that the results from simulation and measurement are in good agreement. The sensing mechanism of the patch structure is also investigated by placing the analyte on top of it. The recommended framework will be useful for biosensors.