A Compact Tree-Shaped Dual-Band Wearable Antenna With Enhanced Far-Field Performance for WBAN Applications

This paper presents a compact, dual-band wearable antenna for wireless body area network (WBAN) applications. The proposed wearable antenna is designed and fabricated using a semi-flexible RT/duroid 5870 substrate enabling dual-band operation resonating at 2.45 GHz and 5.8 GHz ISM bands. The antenna prototype, comprises a rectangular patch that has a hexagonal inlay and a centrally positioned tree-shaped slot, with overall dimensions of 35 × 25 × 0.787 mm³ (0.28 λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> x 0.20 λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> x 0.006 λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>) achieving an impedance bandwidth of 25% (2.21-2.82 GHz) at 2.45 GHz and 7.11% (5.48 -5.78 GHz) at 5.8 GHz. The designed antenna exhibits omnidirectional and bidirectional radiation characteristics with an estimated gain of 2.30 dBi and 4.95 dBi and radiation efficiency of 97.5% and 98.3% at 2.45 GHz and 5.8 GHz respectively. Additionally, validation of both the bending and Specific Absorption Rate (SAR) analyses are carried out and the respective simulated and measured values strongly match providing effective and robust results. Therefore, the proposed design is recommended for Wireless Body Area Network (WBAN) applications including body-worn wearable devices.