An Ultrathin Graphite Based Absorber for Wearable Applications

Abstract

In this paper, a low-cost, flexible, ultrathin absorber comprising a simple square patch-shaped frequency selective surface (FSS) is proposed for wearable applications. The FSS based absorbing structure contains periodic graphite patch pattern placed on a thin paper substrate, and backed with a copper foil-based ground plane. The dimension and periodicity of the unit cell are 0.31λo and 0.36λo respectively, while the thickness of the absorber is approximately λo/85, where λo is the wavelength of free space at 10 GHz. The characteristics of the FSS absorber is optimized in terms of unit cell periodicity, and dielectric substrate height using a full-wave high frequency structure simulator software (HFSS). The effects of the parameters are also examined using equivalent circuit approach. The proposed absorber shows insensitivity towards the angle of incidence as well as angle of polarization. Finally, a prototype model is fabricated, measured, and validated with simulation results. A good agreement is depicted between simulated and experimental models. The proposed absorber finds application in the field of wearable electronics, medical, and automotive applications for effective mitigation of the EMI.