Compact, flexible triple band Sierpinski fractal antenna on a Hilbert patterned ground for W-WBSN

Abstract

Wearable Wireless Body Sensor Networks (W-WBSNs) are the best substitute for traditional healthcare systems by effectively monitoring patients within or remotely from the hospitals. Quite a few tiny sensors linked with one another on the body can efficiently observe the functional status of the human body. The paper introduces a new triple-band step-shaped Sierpinski fractal wearable antenna with a Hilbert fractal slot on the partial ground for W-WBSN applications. It comprises the step-shaped Sierpinski fractal radiator, situated on the upper side, and a partial ground placed on the lower side of the substrate. A partial ground with a Hilbert fractal slot is used to achieve a compact wearable antenna with improved bandwidth and electromagnetic exposure rate characteristics. The antenna is constructed using a flexible Jeans substrate (permittivity 1.7, loss tangent 0.025) of size 60 × 60 mm2 with a thickness of 2.5 mm as it is a potential candidate. It demonstrates an impedance bandwidth of 6%, 7%, and 10.1%, a gain of 2.57 dBi, 3.608 dBi, and 4.19 dBi, the radiation efficiency of 54.19%, 52.5%, and 54.8% at 3.3 GHz, 5.2 GHz, and 5.8 GHz correspondingly in free space. Also, the peak SAR value of 0.64 W/kg, 0.46 W/kg, and 1.17 W/kg at 3.3 GHz, 5.2 GHz, and 5.8 GHz correspondingly, for 10 g of an average human tissue. The compact, flexible low SAR makes the anticipated antenna a superior contender for wireless wearable network applications.