Analysis of the RF Energy Coupling into a Tissue Medium through a Spherical Ferrite Implant

Abstract

The coupling of radio frequency power into a semi-infinite lossy tissue medium with an embedded lossy ferrite sphere is analysed. A magnetic loop near the surface of the lossy medium is taken as the external excitation source. The field induced inside the spherical ferrite implant is determined by solving an integral equation. The kernel of this integral equation is the Green's function of the semi-infinite medium and is expressed in terms of Sommerfeld type integrals. Absorbed power densities inside the ferrite spherical implant and the surrounding lossy medium are computed and are compared for several cases. The efficiency of using ferrite implants in hyperthermia applications is examined and conclusions are presented.