FDTD computation of power deposition in the head for cellular telephones

The finite-difference time-domain method is used to calculate radiation pattern and specific absorption rate (SAR) in the human head due to cellular telephones. For realistic simulation of the ordinary positions of holding the phone, the ear of the model is pressed against the head, the head is tilted at an appropriate angle, and the hand is approximately represented. Cellular phones at frequencies of 835 and 1900 MHz are simulated with monopole above handsets with antenna lengths of U4 and 3 U8. The time-averaged radiated power of 600 mW is used for the 835 MHz test cases, and 125 mW is used for 1900 MHz. The importance of detailed modeling of the tissues is examined by comparing heterogeneous and homogeneous models, and the effect of realistically tilting the phone against the head is also examined. A novel method to truncate the head model to save computer memory is presented.