Split ring resonator-based triple band angle insensitive metamaterial absorber for EMI shielding and stealth applications in microwave frequency range

The proposed triple-band dodecagon asymmetric split ring resonator metamaterial absorber (MA) is designed for versatile applications, primarily focusing on electromagnetic interference (EMI) shielding and stealth across S, C, and X bands. It consists of a copper resonating patch separated by an FR-4 dielectric layer, measuring 8 x 8 mm2, demonstrating remarkable performance. The absorber features four absorption peaks at 2.67, 6.31, 7.11, and 9.46 GHz for the TE mode, with absorption rates exceeding 99 %, as well as for the TM mode, which exhibits at frequencies of 2.67 GHz, 6.33 GHz, 7.14 GHz, and 9.47 GHz, with absorption rates greater than 98.58 %. Furthermore, the MA exhibits excellent absorption characteristics even under up to 45 degrees oblique incidence angles and polarization angles of up to 30 degrees for both transverse magnetic (TM) as well as transverse electric (TE) modes. It possesses single negative characteristics, an EMR (effective medium ratio) value of 14.05, as well as a Q factor (quality factor) exceeding 34 for both TM as well as TE modes. This metamaterial absorber provides triple-band shielding effectiveness (SE) of over 45 dB across the total frequency range, effectively reducing RF signal interference, validated through measured and simulated data. The derived equivalent circuit model aligns with experimental results, enhancing the overall credibility of the findings. In summary, this innovative microwave metamaterial absorber holds great promise for EMI shielding and stealth applications due to its exceptional multi-frequency absorption and shielding capabilities.