Analytical and experimental study of the EM/biological tissues interaction at 1900 MHz

The problem of the interaction between a human head model and a radio-handset at the frequency of 1900 MHz is studied, both theoretically and experimentally. Our analysis is performed using the FDTD method. The input impedance and the radiation pattern of the radio-handset in two cases of with and without the head model are calculated, using a simple homogeneous model. The effect of the radio-handset on the head is studied by calculation of the SAR (specific absorption rate) in four different head models, both homogeneous and heterogeneous. A series of measurements on the input impedance and on the radiation pattern of the radio-handset are performed to confirm the theoretical results. Our studies indicate that the effects of the presence of the head model are a small shift in the centre frequency of the radio-handset and a serious blockage of the radiation pattern toward the head direction. In addition, while the SAR value is not sensitive to the heterogeneity, it reduces by 5% when the neck is added to the model and increases by the same 5% when the size of the the head model decreases by 10%. A comparison of the results obtained with those of other researchers indicates that our models are reliable and can be used in the estimation of the head handset interaction