Robust, Efficient and Low Profile Fractal Enabled EBG Incorporated Wearable Antenna for WLAN Standards

Abstract

A compact, robust Koch fractal combined triangular monopole antenna incorporated with a Sierpinski fractal EBG unit cell array is proposed for integral solutions of wearable devices in WLAN standards. The fractal enabled EBG-Antenna has a modified triangular microstrip that acts as a radiator and a 2X2 array of Sierpinski square EBG unit cells as a reflective surface to enhance the performance also as a shield linking the antenna and human body. The proposed antenna demonstrations and impedance match bandwidth of 32 MHz, a gain of 7.86 dBi, Front to back ratio of 13 dB, Radiation Efficiency of 90.35 % at 2.45 GHz in free space. The EBG-Antenna performs well under different bending conditions and human tissue loading as verified by measurements. The specific absorption rate (SAR) is also evaluated and found within limits as per standards. The computed results accomplished the SAR of 0.302 W/Kg, 0.1423 W/Kg for 1 g, 10 g of tissue, respectively, which demonstrates about a 95 % drop associated with the antenna without EBG. Furthermore, the fractal loading makes the antenna compact; EBG introduced at the underside of the monopole antenna gives a high gain-bandwidth product and disengages the human body and the antenna, making the realized antenna a potential candidate with possible seamless incorporation of specified wearable applications in WLAN standards


(a) The layout of EBG array of unit cells (b) Equivalent circuit and (c) Reflection phase diagram.
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Radiation properties of the anticipated antenna along: (a) y-z, and (b) x-z plane at 2.45 GHz.
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Evaluation of SAR for 10 g of tissue on: (a) Chest and (b) Arm.
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SAR evaluation for chest and arm models
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Description