On attempting to improve the reliability in body-centric communications using fully flexible diversified quad-port MIMO antenna backed with FSS

Abstract Body-centric and body-worn applications have gained much more attention due to the emergence of wearable electronics. Antenna designs suitable for body-centric communications have then become a crucial part of any wearable system. This article introduces an ultra-wideband (UWB) antenna with dimensions of 24 × 18 × 0.8 mm 3 , designed using a flexible jean substrate. Using a slotted patch and defected ground, a wide impedance bandwidth of 15 GHz was achieved. A novel multiple input multiple output (MIMO) configuration with extended swastika-shaped connected ground is proposed to improve the reliability in body-centric communication. Frequency selective surface (FSS) is deployed to reduce specific absorption rate (SAR) and also to achieve directional radiation pattern at a specified frequency range to support both on- and off-body communications. A novel approach of corner-connected inter-rotated square rings was used to achieve wideband response. With the proposed FSS, the antenna renders a good peak gain of 9.1 dB, with the efficiency ranging from 72% to 94% in the UWB spectrum. The FSS proposal also helped in bringing down the SAR within the limits. All the MIMO diversity parameters reported remain good enough, ensuring link reliability. Real-time on-body measurements were carried out at various body parts. The path loss obtained while using the proposed antenna is considerably minimal. Satisfactory results were obtained from the time domain analysis carried out, which ensures good pulse similarity and minimum phase variations.