Electromagnetic Dosimetry Research On The Lnteraction Of Near-Fields Radiated From Wireless-telephone With Human-body

Recent researches ofbiologic-electromagnetism on the electromagnetic dosimetryfocus on the interaction between near-field radiated by the wireless telephone handsetmounted antennas with the human body.The research is of great importance both intheory and in practice,it can offer databases not only for establishing thenon-ionization electromagnetic radiation hygienic standard but also for evaluatingwhether the fie1d radiated by wireless telephone will do harm to the human beings.In this papef, the calculation is made of the field and specific absqrption rate (SAR)distributions in the human body exposed to the near-field radiated from a wirelesstelephone used in the frequency of 900MHz.The highiights in the research are fFirstly, the software to realize FDTD (finite-difference time-domain) method wasprogrammed.The software using the second-order approximation of absorbing boundarycondition and its correCtness is verified.Secondly, the validity of FDTD method used to calculate the near-fielddistributions of antennas is verified by comparing the analytic results of dipolenear-field distribation whh the calculated results by FDTD software. The monopole ofl/4 x length is modeled and its nearfield distributions in the ideal space is calculated.Thirdly, the human head is simulated by a model with inhomogeneous dielectricconstant and conductvity and the mehod of processing the driape is used.Lastly, the field and SAR distributions in the human body are calculated when thewireless telephone is looded at different POsitions of the human body.The wirelesstelephone is located near one side of the ear or in fron of the face.TWo humari headmodels are used, one is rcalistic hcad model,the other is inhomogeneous global headmodel.The conclusions are followedfl.The location of the maximum SAR is near thefeed-in point of monoPole.2.The local SAR is greaty diffeent.3.The maximum SAR isabove the IEEEC95.l-1992's upper safety lind When the head is kept a distance ofl .5cm from the monopole.4.The SAR is small for the head to keep a distance of 5.0cmfrom the monopole and it will do no harm to human body...