SAR Analysis in a Spherical Inhomogeneous Human Head Model Exposed to Radiating Dipole Antenna for 500 MHz - 3 GHz Using FDTD method

Abstract

Analysis of specific absorption rate (SAR) generated by half wave radiating dipole antenna inside a spherical inhomogeneous human head model at the frequency range 500 MHz to 3 GHz using finite difference in time domain (FDTD) method is presented in this paper. The human head is modeled as an inhomogeneous sphere of 19 cm diameter consisting of a uniform core representing human brain, surrounded by two spherical shells representing skull and skin with their respective electromagnetic properties. Maximum local SARs are obtained for the distance between head and antenna in the range of 1.0 cm to 3.0 cm using a dipole antenna of length 14.5 cm. As the distance is increased over 1.0 cm then the value of maximum local SAR induced in the head goes below FCC and IEEE's upper safety limit for input power of 0.6 Watt. Resonant dipole antennas of appropriate length corresponding to several spot frequencies have also been used to observe the maximum local SARs at their resonance frequencies.