Electromagnetic Absorption in the Human Head for Mobile Telephones at 835 and 1900 MHz

Computational and experimental techniques have been used to obtain specific absorption rates or SARs for the human head and neck for a number of typical mobile telephones, including some that are planned for the PCS frequency of 1900 MHz. The FDTD method is used for computations for a high-resolution MRI-based model of the human body with cell sizes on the order of 2 × 2 × 3 mm. For experimental measurements a head-shaped model made of tissue-equivalent materials simulating complex permittivities of skull, brain, muscle, eyes, and ears is used. The SAR distributions are critically dependent on the nature of the antenna and its placement vis à vis the handset and the human body. For many of the mobile telephones the peak SARs for any 1 cm³ of tissue are smaller than 1.6 W/kg considered acceptable by the ANSI/IEEE Safety Guidelines.