<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>

This research presents a new technique which includes the principle of a Bezier curve and Particle Swarm Optimization (PSO) together, in order to design the planar dipole antenna for the two different targets. This technique can improve the characteristics of the antennas by modifying copper textures on the antennas with a Bezier curve. However, the time to process an algorithm will be increased due to the expansion of the solution space in optimization process. So as to solve this problem, the suitable initial parameters need to be set. Therefore this research initialized parameters with reference antenna parameters (a reference antenna operates on 2.4 GHz for IEEE 802.11 b/g/n WLAN standards) which resulted in the proposed designs, rapidly converted into the goals. The goal of the first design is to reduce the size of the antenna. As a result, the first antenna is reduced in the substrate size from areas of 5850 mm 2 to 2987 mm 2 (48.93% approximately) and can also operates at 2.4 GHz (2.37 GHz to 2.51 GHz). The antenna with dual band application is presented in the second design. The second antenna is operated at 2.4 GHz (2.40 GHz to 2.49 GHz) and 5 GHz (5.10 GHz to 5.45 GHz) for IEEE 802.11 a/b/g/n WLAN standards.

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