A procedure to develop realistic numerical models of cellular phones for an accurate evaluation of SAR distribution in the human head

This paper presents an optimization procedure based on the minimization of a cost function and devoted to implement realistic numerical models of cellular phones to be used inside a finite-difference time-domain code. The adopted cost function depends on geometrical and electrical parameters of the phone and quantifies the accuracy of the model by comparing the simulation results with experimental measurements of the near electric and magnetic fields in free space, and of the specific absorption rate (SAR) in a homogeneous cubic phantom. As an example of the application of the proposed optimization method, a numerical model of a commercial phone has been implemented and the power deposition in an anatomically based model of the human head has been computed for various phone positions. The obtained results show that the use of inaccurate phone models can lead to large errors on local SAR evaluation.