Wide-Angle Polarization Independent Triple Band Absorber Based on Metamaterial Structure for Microwave Frequency Applications

This paper presents a wide-angle polarization independent triple-band absorber based on a metamaterial structure for microwave frequency applications. The designed absorber structure is the combination of two resonators (resonator-I and resonator-II). The proposed absorber is ultrathin in thickness (0.012λo at lowest resonance frequency and 0.027λo at highest resonance frequency). The proposed absorber structure offers three absorption bands with peak absorptivities of 99.95%, 95.32% and 99.47% at 4.48, 5.34 and 10.43GHz, respectively. Additionally, it also offers the full width at half maximum (FWHM) bandwidth of 167.2MHz (4.40–4.56 GHz), 178.1MHz (5.25–5.43 GHz) and 393.8MHz (10.24–10.63 GHz), respectively. The metamaterial property of the designed absorber structure has been discussed by using dispersion diagram plot. The designed absorber structure exhibits wide-angle absorption at various oblique incidence angle for both TM and TE polarizations. The absorption mechanism of the designed absorber structure has been analyzed through electric field and surface current distribution plots. The input impedance of the designed absorber (375.67 Ω at 4.48GHz and 346.73 Ω at 10.43GHz) nearly matches the free space impedance. The proposed absorber structure is fabricated and measured. Simulated and measured results are in good agreement with each other.