Complementary Polygon Slot-Based Tunable Metasurface Perfect Absorber with High Tunability

This work discusses a robust reverse design method for the development of a tunable metasurface perfect absorber (TMPA) using a complementary polygon slot. The proposed approach, by default, ensures DC connection across adjacent unit cells to support the biasing of graphene. The narrowband absorber provides frequency agility from 3.72 to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.6 \text{THz}(55.8 \%)$</tex> with the variation in chemical potential from 0.3 to 1 eV. The polarization insensitive TMSA provides absorptivity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(A(f)) \geq \mathbf{9 0 \%}$</tex> for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta \leq \mathbf{6 0}^{\circ}$</tex>. The design is highly compact (Thickness <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$=\lambda_{0} / 31.58$</tex>). Consequently, the TMPA could be employed for multiple uses, including shielding, imaging, sensing, etc.