Specific absorption rate perturbations in the eyes and head by metallic spectacles at personal radio communication frequencies.

The research in this thesis involves the absorption in the human head of microwaves
in the frequency range 0.5 to 3GHz with the excitation positioned in front of the face.
It is hypothesised that metallic spectacles can significantly affect the absorption in the
head.
The effects of metallic spectacles have been primarily investigated using computer
modelling. The finite-difference time-domain (FDTD) is the most common
computational tool used in bioelectromagnetics. For this research an independent,
specially written FDTD code has been used. The accuracy of the code was carefully
validated against controls. Two anatomically accurate heads were implemented into the
FDTD code.
Different shapes and sizes of metallic spectacles were modelled. The materials that the
spectacles were made of were also investigated. Realistic and geometric spectacles were
considered. Vertically and horizontally polarised plane waves as well as vertically and
horizontally orientated dipoles are used as sources. A genetic algorithm (GA) was
employed as a search technique to optimise the spectacles for the specific absorption
rates (SAR) in the eyes and the head.
Measurements were also made of a phantom with metallic spectacles. Results showed
good agreement with the FDTD code. Results confirmed the hypothesis that metallic
spectacles can significantly affect the SAR in the head and particularly in the eyes.