Realistically tilted and truncated anatomically based models of the human head for dosimetry of mobile telephones

Realistically tilted models of the human head have been developed to improve the accuracy of the numerical simulation of coupling between the human head and cellular telephones for the likely tilted positions of the antennas vis a vis the head. A "best fitting" technique is used to rotate an approximately 2/spl times/2/spl times/3 mm resolution model of the human head based on MRI scans of a male volunteer so that the handset may be modeled in the vertical position without stairstep approximation. With this technique, it is possible to move the head with six degrees of freedom in space, instead of the usual three, due to the simple translation thereby allowing a more realistic analysis of the EM coupling between cellular telephones and the human head. Furthermore, to avoid the problem of the large amount of computer memory required for the whole head simulations, we introduced new truncated head models, and the possibility of using them was carefully analyzed. Comparisons of the SAR (specific absorption rate) distributions show that it should be possible to use half head models at 835 MHz and even smaller one-third head models at the personal communications services (PCS) frequency of 1900 MHz. It is shown that, by using the truncated one-third model, it is possible to run with just 42 Mbytes of memory a case that originally needed 85 Mbytes. The truncated models should help to render these large SAR analyses possible by most of the commonly available workstations.