טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentYankilevich Eliezer
SubjectInteraction of Elementary Electromagnetic Sources with
Biological Media
DepartmentDepartment of Electrical Engineering
Supervisor Professor Pinchas Einziger


Abstract

Interaction between electromagnetic sources closely coupled to highly lossy media has been studied extensively in recent years, especially in the areas of cellular communication, medical devices, and hyperthermia-based treatments. Most studies consider specific configurations with variable geometric and physical parameters without making clear separation between contributions of various polarizations generated by a radiating element. In general, an arbitrary source orientation can be expressed in terms of a finite number of fundamental polarizations, each characterized by inherently different electromagnetic characteristics, particularly those associated with local and total Specific Absorption Rate (SAR) behavior. Herein, the focus on the analysis of electric and magnetic dipoles interaction with semi-infinite highly lossy biological medium, studying both transverse electric (TE) and transverse magnetic (TM) horizontal polarizations. This class of canonical models is shown as an effective mean for obtaining physical insight into the basic power absorption mechanisms as well as tight bounds and estimates on power relations and SAR.

The analytic study is carried out by decomposing each polarization configuration into TE and TM modes, resulting in closed-form and readily interpretable expressions for basic power relations, a distinct feature of this approach. In particular, these results are shown to be strongly dependent on the evanescent spectral content of each mode. Further implementation of this modeling approach in 3-D configurations enables a better understanding and an effective design of practical systems comprised of sources radiating in the vicinity of living tissues.