Compact dual-band metamaterial absorber: Enhancing electromagnetic energy harvesting with polarization-insensitive and wide-angle capabilities

A novel compact metamaterial (MM) energy harvester optimized for Wi-Fi frequencies (2.4 GHz and 5.8 GHz) is introduced in this study. The energy harvester exhibits polarization insensitivity and versatility across various incident angles. The energy harvesting (EH) efficiency is evaluated using numerical simulations and practical experiments. The design features ring and octagonal resonators constructed with Rogers RT 5880 Substrate, with each octagonal resonator incorporating a strategically placed gap for lumped elements. The structure's impedance is meticulously aligned with free space to efficiently absorb incident electromagnetic (EM) power with minimal reflection. The simulation outcomes indicate that normal incidence at 2.4 GHz and 5.8 GHz yields high-efficiency levels of 96 % and 98 %, respectively. To validate these results experimentally, we conducted tests in an anechoic chamber using a fabricated 3 × 3 array structure. The results showed a significant correlation between the simulation outcomes and experimental data. The proposed MM energy harvester is highly efficient and shows great promise as an alternative for various microwave applications, such as EH and wireless power transfer.