Unsplit-Field FDTD Simulation of a Mobile Phone Operating Near a Metal Wall

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 unsplit-field finite-difference time-domain (FDTD) simulation scheme was used in the simulation. The simulated physical domain consists of a dipole antenna, a high-resolution 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 operated at 900 MHz 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_avg) absorbed in various human tissues were computed with a distance between an antenna and a metal wall ( Deltal ) as a varied 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<Deltal<9 cm) and (7<Deltal<11 cm).