volume | PIER Journals

Abstract

In this paper we evaluate the potential of a 5-element monopole array incorporated into a handheld device for beamforming in the 5.0-GHz band. The geometry of the handset consists of a 5-element array: four elements located at the handset corners and the fifth-element located at the center. Also, the interaction of the antenna array, mounted on a mobile handset, with a human head phantom is investigated. Firstly, the spatial peak specific absorption rate (SAR) values of 5-element array antennas for mobile handsets in the vicinity of a spherical phantom of a human head are evaluated numerically as a function of the distance between the handset and the head phantom for two different scenarios. Next, the effect of the human head on the handset radiation pattern is studied. The effect of different handset positions on the radiation pattern is also considered. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations of the adaptive arrays elements in a mutual coupling environment for beamforming synthesis. All numerical simulations are performed using the FEKO Suite 5.3 software. To validate the numerical simulations, we first perform two validation tests and compare the numerical results with published simulated and measurement results.

1. Sun, J., J. Sauvola, and D. Howie, "Features in future: 4G visions from a technical perspective," Global Telecommunications Conference, 2001. GLOBECOM '01. IEEE, Vol. 6, 3533-3537, San Antonio, TX, USA, 2001.

2. IEEE C95.1:2005 "Safety levels with respect to human exposure to radio frequency electromagnetic fields, 3 kHz to 300 GHz," IEEE standard, 2005.

3. ICNIRP Guidelines "Guidelines for limiting exposure to timevarying electric, magnetic, and electromagnetic fields (up to 300 GHz)," Health Phys., Vol. 74, No. 4, 1998.

4. Jensen, M. A. and Y. Rahmat-Samii, "EM interaction of handset antennas and a human in personal communications," Proceedings of the IEEE, Vol. 83, No. 1, 1106-1113, January 1995.
doi:10.1109/5.362755

5. Vaughan, R. G. and L. S. Neil, "Evaluation of antenna configurations for reduced power absorption in the head," IEEE Transactions on Vehicular Technology, Vol. 48, No. 5, 1371-1380, September 1999.
doi:10.1109/25.790510

6. Kang, X. K., L. W. Li, M. S. Leong, and P. S. Kooi, "A spheroidal vector wave function analysis of field and SAR distributions in a dielectric prolate spheroidal human head model," Progress In Electromagnetics Research, Vol. 22, 149-179, 1999.
doi:10.2528/PIER98090901

7. Li, L. W., M. S. Leong, P. S. Kooi, and T. S. Yeo, "Specific absorption rates in human head due to handset antennas: A comparative study using FDTD method," Journal of Electromagnetic Waves and Applications, Vol. 14, No. 7, 987-1001, 2000.

8. Kang, X. K., L. W. Li, M. S. Leong, and P. S. Kooi, "A method of moments study of SAR inside dpheroidal human head and current distribution along handset wire antennas," Journal of Electromagnetic Waves and Applications, Vol. 15, No. 1, 61-76, 2001.
doi:10.1163/156939301X00643

9. Kouveliotis, N. K., P. J. Papakanellos, E. D. Nanou, N. I. Sakka, V. S. G. Tsiafakis, and C. N. Capsalis, "Correlation between SAR, SWR and distance of a mobile terminal antenna in front of a experimental validation," Journal of Electromagnetic Waves and Applications, Vol. 17, No. 11, 1561-1581, 2003.
doi:10.1163/156939303772681415

10. Fung, L. C., S. W. Leung, and K. H. Chan, "Experimental study of SAR reduction on commercial products and shielding materials in mobile phone applications," Microwave and Optical Technology Letters, Vol. 36, No. 6, 419-422, March 2003.
doi:10.1002/mop.10780

11. De Salles, A. A., C. R. Ferndadez, and M. Bonadiman, "FDTD simulations and measurements on planar antennas for mobile phones," Microwave and Optoelectronics Conference. IMOC 2003. Proceedings of the 2003 SBMO/IEEE MTT-S International, Vol. 2, 1043-1048, Sept. 2003.
doi:10.1109/IMOC.2003.1242866

12. Stavros, K. and K. S. Nikita, "Study of the coupling between human head and cellular phone helical antennas," IEEE Transactions on Electromagnetic Compatibility, Vol. 46, No. 1, 62-70, February 2004.
doi:10.1109/TEMC.2004.823612

13. Kouveliotis, N. K., S. C. Panagiotou, P. K. Varlamos, and C. N. Capsalis, "Theoretical approach of the interaction between a human model and a mobile handset helical antenna using numerical methods," Progress In Electromagnetics Reasearch, Vol. 65, 309-327, 2006.
doi:10.2528/PIER06101901

14. Klemm, M. and G. Troester, "EM energy absorption in the human body tissues due to UWB antennas," Progress In Electromagnetics Research, Vol. 62, 261-280, 2006.
doi:10.2528/PIER06040601

15. Ding, W., Y. Zhang, P. Y. Zhu, and C. H. Liang, "Study on electromagnetic problems involving combinations of arbitrarily oriented thin-wire antennas and inhomogeneous dielectric objects with a hybrid MOM-FDTD method," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 11, 1519-1533, 2006.
doi:10.1163/156939306779274255

16. Ebrahimi-Ganjeh, M. A. and A. R. Attari, "Interaction of dual band helical and PIFA handset antennas with human head and hand," Progress In Electromagnetics Reasearch, No. 77, 225-242, 2007.
doi:10.2528/PIER07081804

17. Kuo, L.-C., Y.-C. Kan, and H.-R. Chuang, "Analysis of a 900/1800-MHz dual-band gap loop antenna on a handset with proximate head and hand model," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 1, 107-122, 2007.
doi:10.1163/156939307779391722

18. Dietrich, Jr., C. B., W. L. Stutzman, B. Kim, and K. Dietze, "Smart antennas in wireless communications: Base-station diversity and handset beamforming," IEEE Antennas and Propagation Magazine, Vol. 42, No. 5, 142-151, October 2000.

19. Denidni, T. A., D. McNeil, and G. Y. Delisle, "Experimental investigations of a new adaptive dual-antenna array for handset applications," IEEE Trans. Veh. Technol., Vol. 52, No. 6, 1417-1423, Nov. 2003.
doi:10.1109/TVT.2003.816646

20. Yuan, Q., Q. Chen, and K. Sawaya, "Performance of adaptive array antenna with arbitrary geometry in the presence of mutual coupling," IEEE Trans. Antennas Propag., Vol. 54, No. 7, 1991-1996, July 2006.
doi:10.1109/TAP.2006.877158

21. Chim, K.-C., K. C. L. Chan, and R. D. Murch, "Investigating the impact of smart antennas on SAR," IEEE Trans. Antennas Propag., Vol. 52, No. 5, 1370-1374, May 2004.
doi:10.1109/TAP.2004.827513

22. Akimasa, H., S. Mitsuzono, and T. Shiozawa, "Feasibility study of adaptive nulling on handset for 4G mobile communications," IEEE Antennas and Wireless Propagation Letters, Vol. 3, 120-122, 2004.

23. Chen, Q., Y. Komukai, and K. Sawaya, "SAR investigation of array antennas for mobile handsets," IEICE Trans. Commun., Vol. E90-B, No. 6, 1354-1356, June 2007.
doi:10.1093/ietcom/e90-b.6.1354

24. Chen, H.-Y. and H. Yang, "SAR affected by shapes and electrical properities of the human head exposed to the cellular phone," Microwave and Optical Technology Letters, Vol. 42, No. 1, 1-4, July 2004.
doi:10.1002/mop.20189

25. Yoshida, K., A. Hirata, Z. Kawasaki, and T. Shiozawa, "Human head modeling for modeling for handset antenna design at 5 GHz band," Journal of Electromagnetic Waves and Applications, Vol. 19, No. 3, 401-411, 2005.
doi:10.1163/1569393054139679

26. Kennedy, J. and R. Eberhart, "Particle swarm optimization," IEEE International Conferenceon Neural Networks, Vol. 4, 1942-1948, Perth, Australia, 1995.

27. Yu, Q. and O. P. Gandhi, "An automated SAR measurement system for compliance testing of personal wireless devices," IEEE Trans. EMC, Vol. 41, No. 3, 234-244, 1999.

28. Gabriel, C., "Compilation of the dielectric properties of body tissues at RF and microwave frequencies," Brooks Air Force Technical Report AL/OE-TR-1996-0037, 1996.

29. Mahmoud, K. R., M. El-Adawy, R. Bansal, S. H. Zainud-Deen, and S. M. M. Ibrahem, "A comparison between circular and hexagonal array geometries for smart antenna systems using particle swarm optimization algorithm," Progress In Electromagnetics Research, Vol. 72, 75-90, 2007.
doi:10.2528/PIER07030904

30. Mahmoud, K. R., M. El-Adawy, R. Bansal, S. H. Zainud-Deen, and S. M. M. Ibrahem, "Analysis of uniform circular arrays for adaptive beamforming applications using particle swarm optimization algorithm," Int. J. RF Microwave Computed Aided Eng., Vol. 18, 42-52, 2008.
doi:10.1002/mmce.20265

Prof. Korany Mahmoud

Dr. M. El-Adawy

Dr. Sabry Ibrahem

Dr. Rajeev Bansal

Professor Saber Zainud-Deen