Gain Enhanced Dual Band Antenna Backed by Dual Band AMC Surface for Wireless Body Area Network Applications

In this paper, a novel dual band artificial magnetic conductor (AMC) is presented. The AMC is designed to operate at 2.4 GHz, for data transmission over WiFi wireless communication standard, and at 5.8 GHz of the ISM Band, for targeting medical applications. The AMC surface is used as a reflector to make the radiation pattern of dual band monopole antenna unidirectional by reducing the back lobes. The 10 dB impedance bandwidths of the antenna integrated with AMC reflector array are ranging from 2.2 GHz to 2.85 GHz, and from 5.68 GHz to 6.29 GHz. After the incorporation of 4×4 AMC array, peak gain values of the integrated antenna are increased from 1.65 dBi to 4.8 dBi at 2.4 GHz, and from 4.5 dBi to 7.75 dBi at 5.8GHz. Front to back ratio (FBR) of the integrated antenna is also improved by 12 dB at 2.4 GHz, while at 5.8 GHz, it is increased by 20dB. Proximity effects of the antenna on human body are analyzed by using an approximate three layer rectangular model of human body of size 90mm×90mm × 33mm. SAR calculations are done in CST Microwave Studio, using the IEEE/IEC 62704–1 averaging method and the values are found to be 0.28 W/kg, and 0.75 W/kg averaged over 10 g of human tissue at 2.5 GHz and 5.8 GH respectively.