volume | PIER Journals

Abstract

This paper uses the accurate and computationally efficient complex image technique (CIT) to find the electric field and SAR distributions inside a human head illuminated by a finite-length dipole. The human head model used consists of 3 planar layers of lossy dielectrics. The accuracy of the results is verified by comparison with HFSS software. It was found that the CIT requires about 1 minute and 16 MB of RAM, while HFSS requires about 2 hours and 1.5 GB of RAM to find the SAR distribution using a 2.19 GHz Core 2 Due PC. The CIT method can also efficiently solve other types of antennas on other planar head models.

1. International Commission on Non-Ionizing Radiation Protection (ICNIRP) "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)," Health Physics, Vol. 74, No. 4, 494-522, Apr., 1998. Google Scholar

2. Cerrio, G., R. DeLeo, and G. Rosellini, "Evaluation of electromagnetic power deposition in a spherical multilayer head in the near field of a linear antenna," Wireless Netw., Vol. 3, 499-510, 1997.
doi:10.1023/A:1019110829496 Google Scholar

3. Kriticos, H. N. and H. P. Schwan, "Formation of hot spots in multilayered spheres," IEEE Trans. Biomed. Eng., Vol. 23, No. 2, 168-172, Mar., 1976.
doi:10.1109/TBME.1976.324581 Google Scholar

4. Cottis, P. G. and N. K. Uzunoglu, "Focusing properties of dipole arrays placed near a multilayer lossy sphere," Journal of Electromagnetic Waves and Applications, Vol. 4, No. 5, 431-440, 1990. Google Scholar

5. Khalatbari, S., D. Sardari, A. Mirzaee, and H. Sadafi, "Calculating SAR in two models of the human head exposed to mobile phones radiations at 900 and 1800 MHz," PIERS Online, Vol. 2, No. 1, 104-109, 2006.
doi:10.2529/PIERS050905190653 Google Scholar

6. Wait, J. R., "On the electromagnetic response of a conducting sphere to a dipole field," Geophyz., Vol. 25, No. 3, 649-658, Jun., 1960.
doi:10.1190/1.1438747 Google Scholar

7. Kriticos, H. N. and H. P. Schwan, "Hot spots generated in conducting spheres by electromagnetic waves and biological implications," IEEE Trans. Biomed. Eng., Vol. 19, 53-58, 1972.
doi:10.1109/TBME.1972.324159 Google Scholar

8. Joines, W. T. and R. J. Spiegel, "Resonance absorption of microwaves by the human skull," IEEE Trans. Biomed. Eng., Vol. 21, 46-48, Jan., 1974.
doi:10.1109/TBME.1974.324361 Google Scholar

9. Weil, C. M., "Absorption characteristics of multilayered sphere models exposed to UHF/microwave radiation," IEEE Trans. Biomed. Eng., Vol. 22, 468-476, Nov., 1975. Google Scholar

10. Iskander, M. F., P. W. Barber, C. H. Dumev, and H. Massoudi, "Irradiation of prolate spheroidal models of humans in the near field of a short electric dipole," IEEE Trans. Microwave Theory Tech., Vol. 28, 801-807, Jul., 1980. Google Scholar

11. Uzunoglu, N. K. and E. A. Angelikas, "Field distributions in a three-layer prolate spheriodal human body model for a loop antenna irradiation," IEEE Trans. Antennas Propagat., Vol. 35, 1180-1185, Oct., 1987. Google Scholar

12. Li, L., P. Kooi, M. S. Leong, and T. S. Yeo, "Electromagnetic dyadic Green's function in spherically multilayered media," IEEE Trans. Microwave Theory Tech., Vol. 42, 2302-2309, Dec., 1994. Google Scholar

13. Nikita, K. S., G. S. Stamatakos, N. K. Uzunoglu, and A. Karafotias, "Analysis of the interaction between a layered spherical human head model and a finite-length dipole," IEEE Trans. on Microwave Theory and Tech., Vol. 48, No. 11, 2003-2013, 2000.
doi:10.1109/22.884189 Google Scholar

14. Khodabakhshi, H. and A. Cheldavi, "Irradiation of a six-layered spherical model of human head in the near field of a half-wave dipole antenna," IEEE Trans. on Microwave Theory and Tech., Vol. 58, No. 3, 680-690, 2010.
doi:10.1109/TMTT.2010.2040410 Google Scholar

15. Skaropoulos, N. C., M. P. Ioannidou, and D. P. Chrissoulidis, "Induced EM field in a layered eccentric spheres model of the head: Plane-wave and localized source exposure," IEEE Trans. Microwave Theory Tech., Vol. 44, 1963-1973, Oct., 1996. Google Scholar

16. Akram, A. and T. Andrew, "A multi layered model of human head irradiated by electromagnetic plane wave of 100 MHz--300 GHz," Int. J. Sci. Res., Vol. 15, 2005. Google Scholar

17. Omar, A. A., Q. M. Bashayreh, and A. M. Al-Shamali, "Investigation of the effect of obliquely incident plane wave on a human head at 900MHz and 1800 MHz," Int. Journal of RF and Microwave Computer Aided Engineering (RFMICAE), Vol. 20, No. 2, 133-140, 2010. Google Scholar

18. Gandhi, O. P. and J. Y. Chen, "Electromagnetic absorption in the human head from experimental 6-GHz handheld transceivers," IEEE Trans. Electromagn. Compat., Vol. 37, No. 4, 547-558, Apr., 1985.
doi:10.1109/15.477340 Google Scholar

19. Dimbylow, P. J. and O. P. Gandhi, "Finite-difference time-domain calculation of SAR in a realistic heterogeneous model of the head for plane-wave exposure from 600MHz to 3 GHz," Phys. Med. Biol., Vol. 36, No. 8, 1075-1089, 1991.
doi:10.1088/0031-9155/36/8/004 Google Scholar

20. Okoniewski, M. and M. A. Stuchly, "A study of the handset antenna and human body interaction," IEEE Trans. Microwave Theory and Tech., Vol. 44, No. 10, 1855-1864, Oct., 1995.
doi:10.1109/22.539944 Google Scholar

21. Jensen, A. and Y. Rahmat-Samii, "EM interaction of handset antennas and a human in personal communications," Proc. IEEE, Vol. 83, No. 1, 7-17, Jan., 1995.
doi:10.1109/5.362755 Google Scholar

22. Dimbylow, P. J. and S. M. Mann, "SAR calculations in an anatomically realistic model of the head for mobile communication transceivers at 900MHz and 1.8 GHz," Phys. Med. Biol., Vol. 39, No. 9, 1537-1553, 1994.
doi:10.1088/0031-9155/39/10/003 Google Scholar

23. Makris, N., N. Angelone, S. Tulloch, S. Sorg, J. Kaiser, D. Kenedy, and G. Bonmassar, "MRI based anatomical model of the human head for specific absorption rate mapping," Med. Biol. Eng. Comput., Vol. 46, 1239-1251, 2008.
doi:10.1007/s11517-008-0414-z Google Scholar

24. Christ, A., A. Klingenbock, T. Samaras, C. Goiceanu, and N. Koster, "The dependence of electromagnetic far field absorption on body tissue composition in the frequency range from 300MHz to 6 GHz," IEEE Trans. Microwave Theory Tech., Vol. 54, No. 5, 2188-2195, May, 2006.
doi:10.1109/TMTT.2006.872789 Google Scholar

25. Chuang, H. R., "Human operator coupling effects on radiation characteristics of a portable communications dipole antenna," IEEE Trans. Antenna Propag., Vol. 42, No. 4, 556-560, Apr., 1994.
doi:10.1109/8.286229 Google Scholar

26. Chow, Y. L., J. J. Yang, D. G. Fang, and G. E. Howard, "A closed-form spatial Green's function for the thick microstrip substrate," IEEE Trans. on Microwave Theory and Tech., Vol. 39, No. 3, 558-592, 1991.
doi:10.1109/22.75309 Google Scholar

27. Yang, J. J. and Y. L. Chow, "Discrete complex images of a three-dimesnional dipole above and within a lossy ground," IEE Proc., Vol. 138, Part H., No. 4, 319-326, 1991. Google Scholar

28. Yang, J. J., Y. L. Chow, G. E. Howard, and D. G. Fang, "Complex images of an electric dipole in homogeneous and layered dielectrics between two ground planes," IEEE Trans. Microwave Theory Tech., Vol. 40, No. 3, 595-600, Mar., 1992.
doi:10.1109/22.121743 Google Scholar

29. Hojjat, N., S. Safavi-Naeini, and Y. L. Chow, "Numerical computation of complex image Green's functions for multilayer dielectric media: Near FIeld zone and the interface region," IEEE Proc. Microwave, Antennas and Propagation, Vol. 145, No. 6, 449-454, Dec., 1998.
doi:10.1049/ip-map:19982255 Google Scholar

30. Ling, F. and J.-M. Jin, "Discrete complex image method for Green's functions of general multilayer media," IEEE Microwave and Guided Wave Lett., Vol. 10, No. 10, 400-402, Oct., 2000.
doi:10.1109/75.877225 Google Scholar

31. Yuan, M., T. K. Sarkar, and M. Salazar-Palma, "A direct discrete complex image method from the closed-form Green's functions in multilayered media," IEEE Trans. Microwave Theory Tech., Vol. 54, No. 3, 1025-1032, Mar., 2006.
doi:10.1109/TMTT.2005.864138 Google Scholar

32. Yuan, M., Y. Zhang, Z. Ji, and T. K. Sarkar, "Two-dimensional discrete complex image method (DCIM) for closed-form Green's function of arbitrary 3-D structures in general multilayered media," IEEE Trans. Antennas and Propagat., Vol. 56, No. 5, 1350-1357, May, 2008.
doi:10.1109/TAP.2008.922176 Google Scholar

33. Hamming, R. W., Numerical Methods for Scientists and Engineers, 620-622, Dover, 1973.

34. Stratton, J. A., Electromagnetic Theory, 576, McGraw Hill, 1941.

35. Kong, J. A., Electromagnetic Wave Theory, No. 3, John Wiley & Sons, Inc., 1990.

36. Elliott, R. S., Antenna Theory and Design, IEEE Computer Society Press, 2003.

37. Ansoft HFSS, Version 9, of Ansoft Inc..

Dr. Amjad Omar