טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentDikarov Denis
SubjectOptimization of Electromagnetic Power Absorption in a Three
-Dimensional Lossy Circular Cylinder Configuration
DepartmentDepartment of Electrical Engineering
Supervisor Professor Pinchas Einziger
Full Thesis textFull thesis text - English Version


Abstract

Recently, electromagnetic power absorption in biological tissues has become of significant interest. While efficient numerical algorithms have been developed to obtain accurate power distributions in complicated configurations, their physical interpretation and explicit dependence of the problem parameters are still hard to grasp.

    An alternative approach utilizing simplified prototype models has recently led to analytical closed-form solutions. These two-dimensional models, treating both semi-infinite and cylindrical absorbing media in the vicinity of either finite (line current) or surface (planar and circular current sheets) sources, resulted in an explicit dependence of the power relations on both the geometrical and physical parameters and provided an effective mean for obtaining physical insight into the basic power absorption mechanisms as well as tight bounds and estimates on the power relations.

   In some realistic configurations, however, including cellular phone interaction with living tissues, and electromagnetic hyperthermia-based treatments, three-dimensional sources must be incorporated into the model in order to make its implementation effective. Herein, the previously obtained results for point-source radiation in a close vicinity of a semi-infinite lossy medium are extended into a lossy circular cylinder configuration, thereby, accounting for the structure's curvature. The expressions, obtained for both TE and TM polarizations, can be readily interpreted as for the previous (planar) case but with a curvature correction term, which depends, continuously, on the effective surface curvature and the source location. The inclusion of the curvature correction terms for both polarizations, whenever applicable, enables a better understanding and design of prototype systems, which involve electromagnetic sources closely coupled to highly lossy structures.

Keywords: power absorption efficiency, lossy tissues, Leontovich approximation, curvature correction, planar models, cylindrical models.