Theoretical and Numerical Evaluations of Electromagnetic Waves Energy Deposition within the Human Body Due to Exposure to Existent and Emerging Wireless Technologies

Abstract

In this thesis, a comprehensive investigation of the state-of-the-art guidelines for the conducted schemes in the near vicinity of the human body has been provided. The primary objectives of this work have been mainly focused on the electromagnetic (EM) wave exposure at both the microwave and millimetre-wave (mm-wave) frequency bands, along with their thorough analyses for a number of wireless technologies, such as the smart meters (SMs) and multiple-input multiple-output (MIMO) antennas. This work has undertaken a detailed theoretical and numerical modelling, as well as experimental measurements to propose the frameworks for the exposure conditions regarding the advanced wireless systems and applications. The employed numerical methods have been validated using the finite integration technique (FIT)-based simulations. The specific absorption rate (SAR) distributions have been determined using the anatomically realistic human models at various frequency bands. In this regard, each human model is assigned with the age- and frequency-dependent (AFD) dielectric properties, based on the novel expressions. This has then resulted in the representation of dispersive and age-dependent dielectric properties, in order to potentially improve the accuracy of the current assessment methods. Moreover, a number of generalised exposure conditions involving the standing and sleeping postures have been assessed for the home area network operating at the microwave band. The obtained results on the study on the SMs have been partly used by the Public Health England to provide the practical guidelines for the improvement of the services provided for the public. Furthermore, an assessment of the MIMO mobile handset has been performed in two exposure conditions, involving calling and body worn postures. Some aspects of this MIMO study has shown higher absorption levels in comparison with the basic restriction limits. A new SAR estimation approach has also been adopted to address the compliance assessment issues at the mm-wave bands. Finally, this work has identified a number of key factors that cause the high absorption levels in the human body and has provided insight into the efficient techniques in order to reduce such effects.