volume | PIER Journals

Abstract

The fast development of millimeter wave (mmWave) wireless communications and the associated concerns of potential negative impact on human health instigates the study on effects of mmWave frequency on the human body after exposure to electromagnetic field in terms of specific absorption rate (SAR) and temperature rise in computer simulation technology (CST). SAR distributions due to radiating source antenna were investigated using the finite difference time domain (FDTD) method in single and layered human tissues by examining the 1 g SAR (gram mass averaging) and point SAR (without mass averaging) at mmWave frequencies of 28, 40 and 60 GHz. The bioheat equation was used to find the temperature elevation in tissues. The FDTD grid size used in the computation was 1.00, 0.75, and 0.50 mm at 28, 40 and 60 GHz, respectively. The results concluded that at the radiated power of 20 and 24 dBm, SAR levels (without mass averaging) in the tissues at 28 GHz were less than 40 and 60 GHz. It was found that the temperature increase in the three layer model was 2-3 times higher than that in the single layer model. However, the temperature elevation never exceeded 1˚C in all the determined cases which was well below the threshold value for the generation of any adverse thermal effects in the tissues. Moreover, the effect of distance between the source and tissue model was investigated. It was found that the SAR decreased as the distance increased from the radiating source. The results presented here will assist researchers in examining and simulating the performance of upcoming mmWave wireless networks in terms of exposure to human tissues.

1. Zhadobov, M., N. Chahat, R. Sauleau, C. L. Quement, and Y. L. Drean, "Millimeter-wave interactions with the human body: State of knowledge and recent advances," International Journal of Microwave and Wireless Technologies, 2011.

2. Sabbah, A. I., N. I. Dib, and M. A. Al-Nimr, "Evaluation of specific absorption rate and temperature elevation in a multi-layered human head model exposed to radio frequency radiation using the finite difference time domain method," IET Microwave Antennas Propag., Vol. 5, 1073-1080, 2011.
doi:10.1049/iet-map.2010.0172

3. Niu, Y., Y. Li, D. Jin, L. Su, and A. V. Vasilakos, "A survey of millimeter wave (mmWave) communications for 5G: Opportunities and challenges," Wireless Networks, Vol. 21, 2657-2676, 2015.
doi:10.1007/s11276-015-0942-z

4. Millimeter Wave "The battle of the bands,", National Instrument, [online], available: http://www.ni.com/white-paper/53096/en/, 2016.

5., 60 GHz Wireless Technology Overview, http://www.mmwaves.com/products.cfm/product/20-194-0.htm, accessed Nov. 20, 2016.

6. Rashid, M. and S. Hossain, "Antenna solution for millimeter wave mobile communication (MWMC): 5G," International Journal of Scientific Research Engineering & Technology (IJSRET), Vol. 3, 1157-1161, 2014.

7. Chahat, N., M. Zhadobov, L. Le Coq, S. Alekseev, and R. Sauleau, "Characterization of the Interactions between a 60-GHz antenna and the human body in an off-body scenario," IEEE Transactions on Antennas and Propagation, Vol. 60, 5958-5965, 2012.
doi:10.1109/TAP.2012.2211326

8. Robert, F. C., L. U. Jerry, Jr., and L. M. David, "Evaluating compliance with FCC guidelines for human exposure to radiofrequency electromagnetic fields,", OET Bulletin 65, Federal Communications Commission, 1997.

9. Wittig, T., "SAR overview,", www.cst.com, accessed Nov. 25, 2016.

10. Aly, A. A. and M. Piket May, "FDTD computation for SAR induced in human head due to exposure to EMF from mobile phone," Advanced Computing an International Journal, Vol. 5, 2014.

11. David, M. and W. Kwok, "Additional information for evaluating compliance of mobile and portable devices with FCC limits for human exposure to radiofrequency emission,", OET Bulletin 65, Federal Communications Commission, 2001.

12. Gustrau, F. and A. Bahr, "W-band investigation of material parameters, SAR distribution, and thermal response in human tissue," IEEE Trans. on Microwave Theory Tech., Vol. 50, 2393-2400, 2002.
doi:10.1109/TMTT.2002.803445

13. Wu, T., T. S. Rappaport, and C. M. Collins, "The human body and millimeter wave wireless communication systems: Interactions and implications," IEEE International Conference on Communications, London, UK, 2015.

14. Miklavcic, D. and N. Pavselj, "Electric properties of tissues," Wiley Encyclopedia of Biomedical Engineering, 2006.

15. Gabriel, C., S. Gabriely, and E. Corthout, "The dielectric properties of biological tissues: I. Literature survey," Phys. Med. Biol., Vol. 41, No. 11, 2231-2249, 1996.
doi:10.1088/0031-9155/41/11/001

16. Strydom, M. and T. Wittig, "Bioheat simulations with CST studio suite,".
doi:10.1088/0031-9155/41/11/001

17. "IEEE Standard for Safety Levels with respect to Human Exposure to the Radio Frequency Electromagnetic Fields 3 kHz to 300 GHz,", IEEE Std., C95.1, 2005.

18. Kanezaki, A., A. Hirata, S. Watanabe, and H. Shirai, "Parameter variation effects on temperature elevation in a steady-state, one-dimensional thermal model for millimeter-wave exposure of oneand three-layer human tissue," Phys. Med. Biol., Vol. 55, No. 16, 4647-4659, 2010.
doi:10.1088/0031-9155/55/16/003

19. Wang, J. and Q. Wang, Body Area Communications: Channel Modeling, Communication Systems, and EMC, 1st Ed., John Wiley & Sons Singapore PTE Ltd, ISBN: 978-1-118-18848-4, 2013.

20. [ICNIRP1998] 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 Phys., Vol. 74, No. 4, 494-522, 1998.

21. Miguel-Bilbao, S., V. Ramos, and J. Blas, "Comments on assessment of polarization dependence of body shadow effect on dosimetry measurements in the 2.4GHz band," Bio-electromagnetics, Vol. 38, No. 4, 315-321, 2017.

22. Uusitupa, T., I. Laakso, S. Ilvonen, and K. Nikoskinen, "SAR variation study from 300 to 5000 MHz for 15 voxel models including different postures," Phys. Med. Biol., Vol. 55, No. 4, 1157-1176, 2010.
doi:10.1088/0031-9155/55/4/017

Dr. Tooba Hamed

Dr. Moazam Maqsood