In the modern environment, electromagnetic waves from various types of transmission antennas, such as those in cell phones are propagating around the human body. The electromagnetic (EM) wave is absorbed by the human body and some undesirable effects occur in the tissues. The specific absorption rate (SAR) is a useful parameter for measuring these effects. In this study, changes in human body temperature, considered as thermal effects, are computed in a tissue-based analysis of the SAR. The finite difference time domain (FDTD) method and the bio-heat equation are used primarily to calculate the consequent effects. Two-dimensional formulation of FDTD is applied in the computing, and the propagation of the electric field is investigated in two polarizations: transverse electric (TE) wave, and transverse magnetic (TM) wave. The electric field source is kept near the human head which is designed as structured layers.