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This paper presents a comprehensive electromagnetic and thermal analysis of radiation and its impact on human beings, due to the use of various types of commonly used mobile phones and communication antennas. This is one of the first studies that deals with a wide-range comparative investigation of modern cell phones, unlike the majority of existing work, which do not extend beyond the obsolete generic phone case. The rather severe, although overlooked, case of wireless local area network antennas is also considered, due to their increasing use and the large times of exposure associated with them.

A new methodology that facilitates the control of the inherent dispersion error in the case of higher order finite-difference time-domain (FDTD) schemes is presented in this paper. The basic idea is to define suitable algebraic expressions that reflect numerical inaccuracies reliably. Then, finite-difference operators are determined via the minimization of the error estimators at selected frequencies. In order to apply this procedure, an error expansion in terms of cylindrical harmonic functions is performed, which also enables accuracy enhancement for all propagation angles. The design process produces a set of two-dimensional (2-D) FDTD algorithms with optimized frequency response. Contrary to conventional methodologies, the proposed techniques adjust their reliability range according to the requirements of the examined problem and can be, therefore, more efficient in computationally demanding simulations.Index Terms-Finite-difference time-domain (FDTD) method, higher order methods, numerical dispersion.

Abstract-In this paper, an integrated and manifold study of the combined electromagnetic and thermal effects, caused by human exposure to microwave radiation is carried out. In essence, we numerically calculate the amount of electromagnetic power absorbed by biological tissues for various exposure conditions and types of emitting sources, utilizing a detailed model of the human head. The severity of the obtained results is evaluated via comparisons with the guidelines of international safety standards, while further insight is gained by investigating the induced thermal effects. The latter are properly quantified through the solution of the bioheat equation, when combined with the outcome of the electromagnetic simulations. Spatial distributions of the corresponding temperature changes are thus calculated, their relation to the dissipated power is established, and the thermal response of human tissues in marginal cases of exposure is predicted.

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