Quad band metamaterial absorber based on asymmetric circular split ring resonator for multiband microwave applications.

• A novel modified asymmetric circular split ring resonator-based metamaterial is presented for absorber applications in the microwave regime. • The designed metamaterial absorber provides absorption peaks of 97.9%, 99.1%, 99.5% and 99.95% at 4.1 GHz, 6.86 GHz, 11.3 GHz and 13.45 GHz respectively. • Unique characteristics of this absorber is that it exhibits high quality factor and effective medium ratio (EMR) which can be used for sensing and detection purposes. • Metamaterial and absorber properties are explained thoroughly using surface current, electric field, and magnetic field analysis. • Due to miniaturized metamaterial absorber with good EMR, high quality factor and average 99% maximum absorption, this metamaterial absorber can be used for multiband microwave applications. This article presents a metamaterial based on a modified asymmetric circular split ring resonator for absorber applications in the microwave regime. This metamaterial absorber (MMA) exhibits four absorption peaks to cover C, X, and Ku band applications. The MMA unit cell is formed on a low-cost FR4 substrate with electrical dimensions of 0.106 λ 0 × 0.106 λ 0 , for which wavelength, λ 0 is calculated at 4.1 GHz. The resonator of the unit cell is structured with three concentric intercoupled circular split rings with dimensions modified to obtain maximum absorption peaks of 97.9%, 99.1%, 99.5%, and 99.95% at 4.1, 6.86, 11.3, and 13.45 GHz, respectively. Metamaterial and absorber properties are investigated in the analysis of the surface current, electric, and magnetic fields. The unit cell exhibits single negative metamaterial properties with an effective medium ratio (EMR) of 9.15 and quality factor (Q factor) greater than 20. Beyond that, the equivalent circuit of the MMA unit cell is modeled and validated by comparing S 11 obtained from Advanced Design System (ADS) and CST software. The MMA array's absorption properties are also examined in the simulations. Measured results of the unit cell and array correspond well with the result of simulation in terms of absorption at intended frequencies. Given its good EMR, superior quality factor, and high maximum absorption, the MMA can be a good candidate for a multiband absorber in microwave applications like sensing, detecting, notch filtering and to decrease the indirect reverberation and reflections caused by the metallic part of the radar and satellite antennas. [ABSTRACT FROM AUTHOR]