Compact AMC backed wearable button antenna with SAR reduction in multiband WBAN applications

Abstract

In recent years, great emphasis has been lead on research and development of body-centric communication. The technology is important to support remote medical diagnosis and health monitoring, especially for elderly or people with chronic health issues. An important element of body-centric communication system is the central node, usually a wearable antenna. Ultra-Wide Band (UWB) is emerging as a favourable technology for wearable applications due to its low power consumption but high data rate. The UWB based circuits have the ad vantage of being easily fabricated into Monolithic Microwave Integrated Circuits (MMIC). The key challenging element of UWB WBAN is the antenna element, as not only the wearable antenna has to be compact in size but it also needs to cover a wide band along with satisfactory radiation properties. Moreover, the UWB system has to face potential interference from WLAN IEEE 802.11a, HIPER LAN/2 band, downlink of X-band satellite and ITU services. This thesis focuses on a compact UWB structure design and analysis. A planar patch antenna with slots for the purpose of band notches to ovoid interference has been proposed. The UWB antenna is integrated with an Artificial Magnetic Conductor (AMC) layer to enhance its parameters, overall producing a low profile and cost effective antenna. Detailed design evolution from the basic UWB antenna to optimized multilayered UWB structure has been investigated. One of the major contributions of the work lies in its conformance with Federal Communications Commission’s (FCC) Spe cific Absorption Rate (SAR) limit and avoidance of interference with overlapping bands to confirm its suitability in wearable system. An insight on the performance of the structure through simulations and practical characterization has been made. The performance of the fabricated structure is compared with simulated results to assess the performance and confirm stability