Doctor of Philosophy, The Ohio State University, 2012, Electrical and Computer Engineering

There is much interest in developing body-centric wireless communication systems (BWCS) for mobile health care systems. However, the realization of a BWCS is challenging due to the body's interference with the antenna's operation. More specifically, body-worn antennas suffer from impedance detuning, pattern deformation, and gain reduction caused by the body. Therefore, it is important to consider these effects in evaluating body-worn antennas. In this regard, a diversity technique is proposed to improve body-worn antenna performance. More specifically, a channel decomposition method (CDM) is proposed and used to evaluate body-worn antenna systems. The CDM significantly reduces computation time when evaluate body-worn antennas and is applicable to various surrounding environments without recalculation of the more complex interaction. A second contribution of this dissertation is design of a diversity systems which automatically determines the minimum number of antennas while maximizing performance. This approach is employed to design body-worn antenna diversity systems for given communication scenarios. The results obtained via this process demonstrated that this simple method can substantially reduced computation time in designing body-worn antenna diversity system. As a demonstration of the proposed methodology, a vest-mounted UHF body-worn antenna diversity system (BWADS) is developed using 4 light-weight antennas. The proposed BWADS is transparent and unobtrusive to the users but provides performance superior to commercial antennas. A variety of tests were performed to validate the proposed BWADS. It was found that the proposed BWADS provided 7 dB (outdoor) to 16.5 dB (indoor) of higher gain as compared to commercial antennas. The dissertation concludes by proposing other applications of the developed body-worn antennas and design methods.

Committee: John Volakis PhD (Committee Chair); Chi-Chih Chen PhD (Advisor); Fernando Teixeria PhD (Committee Member); Dimitris Psychoudakis PhD (Committee Member) Subjects: Electrical Engineering; Electromagnetics