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<p class="MsoNormal" style="text-align: left; margin: 0cm 0cm 0pt; layout-grid-mode: char;" align="left"><span class="text"><span style="font-family: ";Arial";,";sans-serif";; font-size: 9pt;">The Finite-Difference Time-Domain (FDTD) is the most often used method for evaluating of electromagnetic fields in human tissue. This paper presents a study of heating effects resulted from using a mobile phone operating near a metal wall. The finite-difference time-domain (FDTD) simulation scheme was used in the simulation. The simulated physical domain consists of a dipole antenna, a highresolution human head model and a metal wall enclosed by the Perfectly Matched Layer (PML). In this case, the PML acts as an electromagnetic field absorbing layer and was backed by a perfect electric conductor. An antenna model operated at 900 and 1.8 GHz was used in the simulation. The Specific Absorption Rate (SAR) was computed and averaged on a tissue mass of one gram and ten grams, SAR 1-g and SAR 10-g, respectively. The main purpose of the present research is to compare SAR resulted from a mobile phone operated at two different frequencies (900 MHz and 1.8 GHz) in the close proximity to a metal wall. Also, average powers (P</span></span><span class="text"><span style="font-family: ";Arial";,";sans-serif";; font-size: 7.5pt;">avg</span></span><span class="text"><span style="font-family: ";Arial";,";sans-serif";; font-size: 9pt;">) obsorbed in various human tissues were computed with a distance between an antenna and a metal wall (Δ<em>l</em>) as a varying parameter. Results from the simulation show that the computed SAR 1-g and SAR 10-g values are not exceed the limitation values established by various standard institutes. Also, the average power absorbed in all tissue models with a mobile phone operated at 1.8 GHz has an average power lower than those operated at 900 MHz except for the average power absorbed in muscle (7<Δ<em>l< 9 cm) and eye (7< </em>Δ<em>l</em><11cm).</span></span><span style="font-family: ";Arial";,";sans-serif";; font-size: 9pt;"></span></p>

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In this paper, the Finite-Different TimeDomain (FDTD) schemes were used to find antenna parameters of the simulated dipole antenna. The dipole model has a feeding gap, and there are four FDTD cells around the feeding point. For flexibility in the simulation, the width of the feeding gap can be varied, and results were compared with results from simulations using the Moment Method (MOM). For standard FDTD scheme , there are four equations represent field variations at the center-fed cell. However, this paper proposes a field formulations that reduce from four equations to two equations. In this paper, input impedances and the return losse are ploted as a function of the ratio of dipole's length and a wavelength (L/λ). Simulations show that FDTD schemes give results agree well with the results from MoM. However, FDTD simulation time is much less than the one used in the MOM simulation. Index Terms-Moment Method (MoM), Finite-Difference Time-Domain (FDTD), Perfectly Matched Layer (PML).