FDTD computation of fat layer effects on SAR distribution in a multilayered superquadric-ellipsoidal head model proximate to a dipole antenna at 900/1800 MHz

This paper presents FDTD computation of fat layer effects on the SAR distribution in a head model proximate to a dipole antenna at 900/1800 MHz. The human head is modeled to be a multi-layered superquadric ellipsoid, which is flexible to model a sphere, ellipsoid, square cube, or rectangular cube. The ellipsoidal head model (with the ears) comprises 9 different tissues (if with a fat layer) of skin, cartilage, fat, muscle, bone, blood, nerve, brain, and eye-lens. A finite radius half-wavelength dipole antenna (corresponding to a length of 16.0/8.0 cm at 900/1800 MHz) is used for study. Three cases of the fat layer in the head model are considered: (1) without, (2) with a 2.5-mm, and (3) with a 5.0-mm thickness fat layer. It is observed that the head model with a 2.5 or 5.0-mm fat layer has almost the same SARs (for peak-SAR, about 18 mW/g at 900 MHz, and 24 mW/g at 1800 MHz). However, the head without a fat layer has lower SARs at 900 MHz (for peak-SAR, about 15 mW/g) but higher SARs at 1800 MHz (for peak-SAR, about 28 mW/g) than those values of the head with a fat layer.