MODELING OF PENETRATING ELECTROMAGNETIC FIELDS OF MOBILE PHONES IN EXPERIMENTAL ANIMALS

1. DejanKrstić, DarkoZigar, DejanPetković, NenadCvetković, Vera Marković, NatašaĐinđić, Boris Đinđić * University of Niš, Faculty of Occupational Safety in Niš, Čarnojevića 10a, Niš, Serbia, e-mail: dejank@znrfak.ni.ac.yu ** University of Niš, Faculty of Electronic Engeenering Nis, Aleksandra Medvedeva 14, Niš *** University of Niš, Medical Faculty in Niš, BulevarZoranaĐinđića 81, Niš MODELING OF PENETRATING ELECTROMAGNETIC FIELDS OF MOBILE PHONES IN EXPERIMENTAL ANIMALS

2. EM Radiation &Biological Effects • electromagnetic radiation, electromagnetic pollution or electromagnetic smog • undesirable phenomena (not confirmed by the good) • biological effects, performed on experimental animals. Fig. 1 - Experimental animals with a mobile test phone [3]

3. Biological effects LINK with Absorbed energy • Penetrating electromagnetic field is almost impossible to measure • Penetrating field in the tissue must be calculated • Numerical methods in electromagnetics (integral method, differential and variation method) • Commercial software packages

4. What is object of MODELING ? • Model of the source (mobile phone) with the antenna pattern characteristic, • Experimental animal model with the actual characteristics of tissues • Model of wave propagation in half-conductive environment, i.e. the choice of numerical simulation methods (FDM, MoM, FDTD, FIT, etc.).

5. Electromagnetic model of mobile phone Three types of mobile • Mono-block phone with a with monopole antenna which is placed on the top of the mobile phone (a), • Mono-block phone with a planar inverted-F antennas - PIFA (b and c) • Flip-down phone with a PIFA (d).

6. Numerical Simulation Method - FDTD Method (Finite Difference Time Domain) • FDTD solves Maxwell’s equations in the time domain. This means that the calculation of the electromagnetic field values progresses at discrete steps in time. • Main reason for using the FDTD approach is the excellent scaling performance of the method as the problem size grows. • As the number of unknowns increases, the FDTD approach quickly outpaces other methods in efficiency. • FDTD has been identified as the preferred method for performing electromagnetic simulations for biological effects from wireless devices [3, 4, 7]. • Simulation program was carried out REMCOM XFDTD [8]

7. Model of experimental animals • It is significant to known the real position of all tissues in animal body and their electromagnetic characteristics. • These complimentary animal meshes are provided by The Radio Frequency Branch of the Human Effectiveness Division of the Air Force Research Lab at Brooks Air Force Base [11]. • Real 3D model with all tissue and resolution of model is 1mm. • Model have 47 diferent tissues and parts.

8. EM characteristics for some biological tissue experimental animal – rats [11]

9. Horizontal cross section of Rat model

10. SIMULATION PROCESS • In the simulation process with REMCOM XFDTD program is used a source of power 1W. • The results for the component EM fields in free space have been compared with the values measured by fieldmeter AARONIA HF6080. • The results matched have been satisfactory. • Simulated is real cage with rats and mobile phone in two possition.

11. SIMULATIONPROCESS Case 1 - Antena is near to the head

12. SIMULATION PROCESS Case 2 - Antena is near to the stomach

13. Electrical field Electric field in model of rat

14. Electrical field

15. Case 1 – Distribution of EM field Distribution of SAR in trunk of model cross section liver Electric field in model of rat Distribution of SAR in head of model cross section of brain and eye tissue

16. Case 2 – Distribution of EM field Electric field in model of rat Distribution of SAR in trunk of model cross section liver Distribution of SAR in head of model cross section of brain and eye tissue

17. RESULTS OF SIMULATION Tab. 2 - Calculation Electrical field in some part of body in model of rat.

18. RESULTS OF SIMULATION Tab. 3 - Calculation SAR in some part of body in model of rat.

19. SAR - Specific Absorption Ratioin the different cross section of head

20. CONCLUSION • The results of electric field distribution in the rats bodies suggest that there is an unequal distribution of the fields, which depends on the position of the sources and characteristics of each tissue. • It is important to note that there are tissues which absorb 10 times higher amounts of energy the tissues adjacent to them. • Precise locate point of maximum SAR indicate the possible biological effects of radiation on these tissues. • These effects were presented and discussed in various papers which analyzed biochemical indicators of the effects of electromagnetic fields. • Such calculation enables us to develop the biological quantifiers of the effects of electromagnetic fields, which is studied by dosimetry. • Thus obtained quantifiers could be applied on the human tissue. Acknowledgement: This work was supported by the project III43011 and III43012 of the Serbian Ministry of Education and Science.