Electric field integral equation solution for a microstrip applicator radiating into a layered biological structure

The use of microstrip antennas in hyperthermia treatment of cancer is considered. Interest is focused on the power deposition inside a biological tissue, which necessitates a correct evaluation of the surface current on the microstrip patch. To simplify the problem, the biological tissue is modeled as a two-dimensional multilayered structure. A coupled integral equation technique is proposed to analyze the radiation of a microstrip antenna. The method is approximate as it neglects part of the exciting current and the number of coupled equations would become too large to handle in the case of a multilayered structure. The approach is based on the electric field integral equation. The basis functions take the singular behavior of some current components at the edges of the microstrip patch into account. Special attention is given to correct modeling of the excitation. The numerical results focus on the power deposition inside the biological tissue. The method allows a rather fast evaluation of the fields at every point of space, once the unknown surface current on the microstrip antenna has been determined.<>