An implanted spherical head model exposed to electromagnetic fields at a mobile communication frequency.

Can cellular phones and personal communication systems base station antennas affect the active or passive implantable medical devices adversely? Concerns over the possible harmful effects of nonionizing irradiaton upon implanted medical devices have been present for many years. Key issues to address are the questions of whether mobile phones have a detrimental effect on implants, and how the interaction of the handset with the body can be minimized in order to both alleviate public fears and improve handset antenna performance and new implant designs. This paper presents a thorough investigation of the scattering of an electromagnetic (EM) wave from a perfectly conducting implant (a cylindrical wire and a very thin cylindrical disk) of electrically small radius (of resonant length), embedded eccentrically into a dielectric spherical head model by a dipole antenna (0.4 wavelength) at 900 MHz. The dyadic Green's function (DGF) for spherical vector wave functions is employed. Analytical expressions for the scattered fields of an implant embedded head model is obtained. Numerical results from analytical expressions are computed for this problem and then compared with the results from the same model using the finite-difference time-domain, EMU-FDTD electromagnetic simulator. Good agreement is observed between the analytical results on the proposed method in comparison with the FDTD method.