Bandwidth analysis of microwave metamaterial absorber with a resistive frequency selective surface by using an equivalent circuit model

Abstract

Bandwidth analysis of a resistive frequency selective surfaces (FSS) in microwave metamaterial absorber is very important for bandwidth-targeted design of the FSS pattern. A useful analysis for the case of a thin grounded dielectric substrate was performed a decade ago, however in the cases of thicker dielectric substrates it is not clear how to design the FSS pattern in order to achieve the largest bandwidth. Without the assumption that the grounded dielectric substrate is thin, we investigated relations between the bandwidth and the FSS reactance and revealed explicit expressions of the FSS reactance for the largest bandwidth. Although in full wave simulations for demonstrating the validity of the bandwidth analysis we assumed exemplary the square loop element, the bandwidth analysis is applicable for general FSS element structures. Our findings give design guidance for the FSS patterns of perfect absorbers in order to achieve the largest bandwidth.