טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentDiana Soldea
SubjectOptimization of the Power Absorption Efficiency in a
Highly Lossy Biological Medium
DepartmentDepartment of Electrical Engineering
Supervisors Professor Einziger Pinchas
Professor Emeritus Mizrahi Joseph


Abstract

Electromagnetic power absorption in a biological medium is a well-known phenomenon. Its evaluation requires, in general, a solution of the 3-D frequency dependent wave equation in complex configurations. Herein, we focus on canonical models which lead to explicit analytic solutions for the optimization problem. These solutions being first order approximations of the general 3-D problems, result in closed-form representations for the power absorption efficiency in terms of the electrical and geometrical parameters of the medium. This research aims on understanding the absorption process using several canonical models. The models are solved in an analytic and complete way. The set of canonical problems include elementary sources only (dipole, line source, plane wave) that are in connection with absorbing simple bodies (half-space, cylinder, sphere). This canonical models enable the understanding of the absorption phenomenon as a function of the radiation source and the geometry of the absorption bodies. The results depend continuously and explicitly on the physical parameters of the tissues and of the type and location of excitation source location. They are shown to be closely related to specific absorption rate (SAR estimations), which are crucially important in electromagnetic radiation exposure standards for biological tissues. The canonic analytic models can be implemented in the case of the cellular phone model in the presence of the human head. The results presented herein are expected to be effectively utilized in the analysis and optimization of microwave heating and waveguide based therapeutic hyperthermia systems for biological tissues.