Hrvoje Dodig

Electromagnetic-thermal Analysis For Human Exposure To High Frequency (hf) Radiation

The paper aims to review some electromagnetic-thermal dosimetry methods for the assessment of human exposure to high frequency (HF) electromagnetic fields. The analysis approaches are based on certain integral/differential equation formulations and related numerical solution procedures for the calculation of specific absorption rate (SAR) and related temperature increase in a tissue. Illustrative computational examples for the human eye and the human brain exposed to HF electromagnetic fields are given in the paper. Also, some numerical results for the transcranial magnetic stimulation (TMS) are presented as an example of biomedical application of electromagnetic fields. The obtained numerical results for SAR are compared against exposure limits proposed by ICNIRP (International Commission on Non Ionizing Radiation Protection).

A Study on the Use of Compound and Extracted Models in the High Frequency Electromagnetic Exposure Assessment

The paper presents the numerical results for the induced electric field in the various models of the human eye and the head. The comparison between the extracted or the single organ models and the compound organ models placed inside realistic head models obtained from the magnetic resonance imaging scans is presented. The numerical results for several frequencies and polarizations of the incident electromagnetic (EM) plane wave are obtained using the hybrid finite element method/boundary element method (FEM/BEM) formulation and the surface integral equation (SIE) based formulation featuring the use of method of moments, respectively. Although some previous analysis showed the similar distribution of the induced electric field along the pupillary axis obtained in both eye models, this study showed this not to be the case in general. The analysis showed that the compound eye model is much more suitable when taking into account the polarization of the incident EM wave. The numerical results for the brain models showed much better agreement in the maximum values and distributions of the induced surface field between detailed models, while homogeneous brain model showed better agreement with the compound model in the distribution along selected sagittal axis points. The analysis could provide some helpful insights when carrying out the dosimetric analysis of the human eye and the head/brain exposed to high frequency EM radiation.

HYBRID FEM/BEM FOR HUMAN HEADS EXPOSED TO HIGH FREQUENCY ELECTROMAGNETIC RADIATION

In this paper the hybrid finite element/boundary element method (FEM/BEM) is used to analyze the human head exposed to plane wave radiation. The radar cross-section (RCS) of a coated sphere at interior resonance frequency obtained using the proposed method showed an excellent agreement with the analytical Mie series solution, thus verifying the validity of the formulation. High frequency electromagnetic wave incident on the human head representing an unbounded scattering problem is formulated via the Stratton-Chu expression, while the interior domain is governed by the vector Helmholtz equation. Some computational examples for the induced electric field are presented. Numerical results showed the highest values of the induced fields around the ocular region and the nose. The presented method is found to be useful in the assessment of the induced fields in the anatomically realistic human models.

Methods Of Health Risk Assessment For Human Exposure To High Frequency Electromagnetic Fields

The paper reviews some topics in human exposure to high frequency (HF) electromagnetic fields based on certain integral equation formulations and related numerical solution procedures. Illustrative computational examples are related to the human eye and the human brain exposed to HF radiation. The obtained numerical results for specific absorption rate (SAR) are compared against exposure limits proposed by ICNIRP (International Commission on Non Ionizing Radiation Protection).