An Ultrathin Polarization Free Asterick-Shaped Metamaterial Absorber with Quad-Band Characteristics

In this paper, a quad-band absorber is proposed and developed, which is exhibiting ultrathin and polarization insensitive behaviour. It has been designed to be operated in S, C, and Ku bands with absorptions peaks at more than 95%. The proposed absorber is implemented on a FR4 glass epoxy laminate with an equivalent electrical thickness of 0.0108 λ0, where λ0 is the wavelength corresponding to the lowest frequency of operation. This confirms the ultrathin nature of the structure. The absorption performance of the proposed structure has been characterized under normal and oblique incidences followed by their experimental verification. Presented results demonstrate highly polarization-independent behavior of the proposed absorber due to its symmetric geometry. Also, the electromagnetic field distributions have been studied to acquire better insight of the absorption mechanism corresponding to distinct elements present in the structure. It is characterized in terms of its behavior as metamaterial, which ensures the miniaturization. The proposed absorber is suitable to be used in applications like radar cross section reduction, stealth technology, radio frequency identification, and electromagnetic compatibility.