Compact eight-shaped ISM-I band wearable antenna for wireless body area network applications

Abstract

Abstract The design and analysis of the electrically small eight-shaped wearable antenna for both on- and off-body communication is proposed in this paper. An eight-shaped radiating structure is placed over the jeans substrate and an I-shaped slot is introduced in the ground plane which makes the antenna resonates at the ISM-I band (2.4 GHz). The antenna has a compact size of 0.30λ 0 × 0.20λ 0 × 0.001λ 0, where λ 0 is the free space wavelength at the resonance frequency. The impedance bandwidth (≤−10 dB) of the antenna is 6.1 % and 5.8 % in free space and presence of a human body phantom respectively. The antenna design exhibits good gain along with an improved omnidirectional radiation pattern. The specific absorption rate (SAR) of the antenna averaged over 1 g of tissue is 0.21 W/kg at 2.45 GHz which is far below the FCC standard. The paper also discusses the bending analysis and the fundamental size limitations of the small antenna, concluding that it is suitable for practical use. The simulated results of the prototype are validated by the measured results.