Hexagon Shaped UWB Monopole MIMO Antenna for WBAN Applications

A hexagon shaped four-port ultra-wideband (UWB) MIMO antenna is proposed for WBAN application. The substrate used is Rogers 5870 which is flexible and biocompatible. The single antenna's and MIMO antenna's total layouts are $28 \times 25\times 0.76$ cubic millimeter and $58 \times 58\times 0.76$ cubic millimeter. The diversity parameters like $\text{ECC} < 0.1,\ \text{DG} > 9.6$ dB, $\text{CCL}< 0.2$ bits/s/Hz and $\text{TARC} <-12\ \text{dB}$ are calculated. The proposed antenna's maximum gain and efficiency are 3.957 dBi and 98.5% respectively. To guarantee that the proposed antenna does not expose human tissues to radiation, a specific absorption rate (SAR) analysis is assisted. For 1 gram of tissue, SAR values of $0.513\ W/Kg$ is obtained at 4 GHz and 0.316 W/kg is achieved at 8 GHz.