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.
