Numerical Simulation And Research On Dielectric Properties Of Age-related Biological Tissues

At present, the data of the dielectric property of adults is mostly used in the safety assessment of the electromagnetic exposure of the young and the infants dosimetry, which will bring some errors to the evaluation results. From the literature report, the biological characteristics of pig and human are highly agreed. The data that based on the biological tissues of pigs are used. Parameters of four order Cole-Cole model are established respectively for the three age groups of infants, young and adults, and the safety assessment of the human head exposed to the mobile phone are investigated under the radiation of the mobile phone. Specific content are as follows:(1) The theoretical research and the experimental measurement of the biological dielectric properties are introduced. In this thesis, the characteristics of the dielectric relaxation, dispersion and the Cole-Cole model are described in detail.(2) The four order Cole-Cole model can be used to describe the biological dielectric properties of the whole frequency band. Based on the characteristics of the least square method and the fast convergence rate of Newton iterative method, data of 15 kinds of tissues are fitted by the least square method and Newton iterative method, and the fitting parameters of the four order Cole-Cole model are obtained. Parameters of the four order Cole-Cole model are used to predict the dielectric parameters of different age groups.(3) A Planar Inverted F antenna(PIFA) is designed(the center frequency is 835MHz) and used for the mobile phone antenna. With the three sphere models of different ages, the SAR in the head are calculated. The results show that the SAR values of the head under the mobile phone radiation are within safety limits, but the SAR in the head will decrease with the increase of ages. Therefore, children should be paid more attention to avoid prolonged exposure to electromagnetic radiation environment.