Traditional copper-based planar antennas have traditional disadvantages for wearable applications because of poor flexibility, deteriorated signal under deformation, expensive and environmental problems. To solve these issues, graphene has been proposed as a radiating material with high electrical conductivity, great flexibility, and the possibility of being printed on low-cost textile/paper substrates. In this study, graphene was used as a conductive material in an a two-port MIMO antenna for wearable smart communication. The graphene MIMO wearable antenna is printed on Jeans with a dielectric constant of 1.67, and an overall dimension of 35 × 55 mm³. The antenna operates in a multiband mode within the 5G sub-6 GHz spectrum, covering two distinct frequency ranges of 3.1–4.3 GHz and 4.9–6.0 GHz. This makes it a strong candidate for wearable 5G sub-6 GHz terminals, body-centric wireless communication systems, and short-range WLAN/ISM-based smart wearable devices. In addition, higher-order resonant bands at 8.25–9.4 GHz and 10.82–14.4 GHz are observed, indicating that the proposed design inherently exhibits wideband characteristics in the X-band region. The graphene is highly electrically conductive being 4.02 × 105 S/m. The SAR analysis was carried out for the entire bandwidth, and it can be seen that energy absorption tends to be more restricted by increasing the skin depth (SC and OC) with higher frequency because of the dependence of dielectric properties on frequency. The maximum measured SARs are quite low below the ICNIRP safety limits 0.84 W/kg averaged over 10 g of tissue at an input power of 0.5 W, and hence it indicates that the proposed graphene-based MIMO configuration is a suitable solution for long-term wearable applications as it does not impose any health threats to the user.
Al-Gburi et al. (Sat,) studied this question.