A low sar value wearable antenna for wireless body area network based on amc structure

Abstract

This paper proposes a wearable antenna for Wireless Body Area Network (WBAN) that operates at the 2.45GHz medical band. The antenna is enabled by coplanar waveguide, and the impedance bandwidth of the antenna is expanded by combining a circular slot with asymmetric slots. In order to reduce the radiation of the antenna back lobe and improve the antenna gain, a new 2×2 Artificial Magnetic Conductor (AMC) is designed and loaded under the monopole antenna. The radiation of antenna back lobe is effectively reduced due to the addition of AMC reflector. Also, the front-to-back ratio of the demonstrated antenna is higher than 20 dB, achieving a forward gain of 7.47 dBi and Specific Absorption Rate (SAR) lower than 0.15 W/kg, in the ISM band. For further research, the antenna is fabricated and tested, showing a strong agreement between simulation and measurement. Meanwhile, the antenna has stable performance under the bending condition, meeting the practical application requirements of wearable equipment.