Wearable antennas for personal wireless networks

• Main Author: Zhu, Shaozhen
• Published: University of Sheffield 2008
• Subjects: 621.3
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489872

In this study, we mainly characterize the wearable antenna system for off-body communications with respect to two conventional wireless communication systems as, cellular mobile systems (pes, GSM and UMTS) and wireless local area networks (WLAN). Unlike antennas embedded in portable devices, the complicated bodycentric environment has emerged with special requirements for wearable antennas design, like compact dimensions, light weight and flexible structure, hidden or water proofmg, and most importantly, capable of providing certain radiation shielding into the human body. This thesis aims to fmd an optimum solution to meet the particular requirements ofwearable antenna design. The first part is primarily concerned with characterising the electromagnetic properties of some textile and leather materials. Both insulating and conducting materials are investigated for using as substrate and radiating elements of high perfonnance textile antennas. Then a few of new antenna designs are proposed in the second part. These antennas are made out of textile and leather materials. They are low profIle, planar in geometry, and most importantly, they are capable to provide multi-operations with considerable wide bandwidth. An electromagnetic band gap structure is studied as it can provide a high impedance ground plane for low profIle antennas. The EBG plane can provide a perfect shielding layer for the body, and reduce the radiation toward the body significantly. Furthermore, the EBG plane is able to reduce the detuning of the antenna when placing near the body without serious bandwidth reduction, increase antenna gain and reduce mutual coupling from other devices. The final part carries out a series ofexperiments which can represent the body-centric environment These include bending, washing, wearing, coupling and SAR investigations. Antenna and EBG performances under body worn environment are tested and discussed in this thesis.