volume | PIER Journals

Abstract

The aim of this paper is to prove that the power generated by a wearable textile patch antenna experiences reduced absorption in the phantom when the antenna ground-plane is increased. First, the dedicated human torso-equivalent phantom and two antennas were fabricated, which are multi-layered, with orientation normal to the body and made of the same materials. One of the antennas has a double in size ground-plane with regards to the other antenna, while the rest of their dimensions are identical. According to the proposed measurement procedure, once the radiation efficiencies of both antennas are measured in free space and with the phantom, the total absorption coefficient and the phantom losses are evaluated. The comparison of the measurement results proves that the increased ground-plane reduces the absorption on the phantom body of the antenna EM power (by 30.5%). Simulations and measurements were found in good agreement, with maximum deviation between the two up to 6% in terms of radiated efficiency. Hence, the proposed experimental evaluation of the impact of the ground-plane size of a wearable textile patch antenna on the reduction of the power absorbed by the user's body can be considered as a simple, reliable and cost-effective measurement method.

1. Hombach, V., K. Meier, M. Burkhardt, E. Kuhn, and N. Kuster, "The dependence of EM energy absorption upon human head modeling at 900 MHz," IEEE Trans. Microwave Theory Tech., Vol. 44, 1865-1873, Oct. 1996.
doi:10.1109/22.539945 Google Scholar

2. Meier, K., V. Hombach, R. Kastle, R. Y.-S. Tay, and N. Kuster, "The dependence of electromagnetic energy absorption upon human head modeling at 1800 MHz," IEEE Trans. Microwave Theory Tech., Vol. 45, 2058-2062, Nov. 1997.
doi:10.1109/22.644237 Google Scholar

3. Balzano, Q., O. Garay, and T. Manning, "Electromagnetic energy exposure of simulated users of portable cellular telephones," IEEE Trans. Veh. Technol., Vol. 44, 390-403, Aug. 1995.
doi:10.1109/25.406605 Google Scholar

4. Kobayashi, T., T. Nojima, K. Yamada, and S. Uebayashi, "Dry phantom composed of ceramics and its application to SAR estimation," IEEE Trans. Microwave Theory Tech., Vol. 41, 136-140, Jan. 1993.
doi:10.1109/22.210240 Google Scholar

5., URL: https://indexsar.com/..
doi:10.1109/22.210240 Google Scholar

6., URL: https://www.speag.com/products/isar2/isar2-systems/..
doi:10.1109/22.210240 Google Scholar

7. Sager, M., M. Forcucci, and T. Kristensen, "A novel technique to increase the realized efficiency of a mobile phone antenna placed beside a head-phantom," IEEE Antennas and Propagation Society International Symposium, Vol. 2, 1013-1016, Columbus, Ohio, USA, Jun. 2003. Google Scholar

8. Holopainen, J., J. Ilvonen, O. Kivekas, R. Valkonen, C. Icheln, and P. Vainikainen, "Near field control of handset antennas based on inverted top wavetraps: Focus on hearing-aid compatibility," Antennas and Wireless Propagation Letters (AWPL), Vol. 8, 592-595, 2009.
doi:10.1109/LAWP.2009.2022352 Google Scholar

9. Picher, C., J. Anguera, A. And´ujar, et al. "Analysis of the human head interaction in handset antennas with slotted ground planes," IEEE Antennas Propag. Mag., Vol. 54, No. 2, 36-56, 2012.
doi:10.1109/MAP.2012.6230717 Google Scholar

10. Andujar, A., J. Anguera, C. Picher, and C. Puente, "Ground plane booster antenna technology. Human head interaction: Functional and biological analysis," European Conference on Antennas and Propagation, EuCAP 2012, Prague, Czech Republic, 2012. Google Scholar

11. Nishikido, T., Y. Saito, M. Hasegawa, H. Haruki, Y. Koyanagi, and K. Egawa, "Multi-antenna system for a handy phone to reduce influence by user's hand," 6th International Symposium on Antennas, Propagation and EM Theory, 2003, Proceedings, 348-351, Beijing, China, 2003.
doi:10.1109/ISAPE.2003.1276699 Google Scholar

12. Hirata, A., T. Adachi, and T. Shiozawa, "Folded-loop antenna with a reflector for mobile handset at 2.0 Hz," Microwave & Opt. Tech. Lett., Vol. 40, No. 4, 272-275, 2004.
doi:10.1002/mop.11350 Google Scholar

13. Islam, M. T., M. R. I. Faruque, and N. Misran, "Design analysis of ferrite sheet attachment for SAR reduction in human head," Progress In Electromagnetics Research, Vol. 98, 191-205, 2009.
doi:10.2528/PIER09082902 Google Scholar

14. Wang, J., J., O. Fujiwara, and T. Takagi, "Effects of ferrite sheet attachment to portable telephone in reducing electromagnetic absorption in human head," 1999 IEEE International Symposium on Electromagnetic Compatability, Vol. 2, 822-825, Symposium Record (Cat. No.99CH36261), Seattle, WA, 1999. Google Scholar

15. Hanafi, N. H. M., M. T. Islam, N. Misran, and M. R. I. Faruque, "Numerical analysis of aluminium sheet for SAR reduction," Proceeding of the 2011 IEEE International Conference on Space Science and Communication (IconSpace), 281-285, Penang, 2011.
doi:10.1109/IConSpace.2011.6015901 Google Scholar

16. Kwak, S. I., D. U. Sim, J. H. Kwon, and H. D. Choi, "Comparison of the SAR in the human head using the EBG structures applied to a mobile handset," 2007 European Microwave Conference, 937-940, Munich, 2007.
doi:10.1109/EUMC.2007.4405348 Google Scholar

17. Hwang, J. N. and F. C. Chen, "Reduction of the peak SAR in the human head with metamaterials," IEEE Transactions on Antennas and Propagation, Vol. 54, No. 12, 3763-3770, Dec. 2006.
doi:10.1109/TAP.2006.886501 Google Scholar

18. Rani, R., P. Kaur, and N. Verna, "Metamaterials and their applications in patch antenna: A review," International Journal of Hybrid Information Technology, Vol. 8, No. 11, 199-212, 2015.
doi:10.14257/ijhit.2015.8.11.17 Google Scholar

19. Yimdjo Poffelie, L. A., P. J. Soh, S. Yan, and G. Vandenbosch, "A high-fidelity all-textile UWB antenna with low back radiation for off-body WBAN applications," IEEE Transactions on Antennas and Propagation, Vol. 64, No. 2, 757-760, 2016.
doi:10.1109/TAP.2015.2510035 Google Scholar

20. Aun, N. F. M., P. J. Soh, A. A. Al-Hadi, M. F. Jamlos, G. A. E. Vandenbosch, and D. Schreurs, "Revolutionizing wearables for 5G: 5G technologies: Recent developments and future perspectives for wearable devices and antennas," IEEE Microwave Magazine, Vol. 18, No. 3, 108-124, May 2017.
doi:10.1109/MMM.2017.2664019 Google Scholar

21. Gil, I. and R. Fernandez-Garcıa, "SAR impact evaluation on jeans wearable antennas," 2017 11th European Conference on Antennas and Propagation (EUCAP), 2187-2190, Paris, 2017.
doi:10.23919/EuCAP.2017.7928181 Google Scholar

22. Bhattacharjee, S., M. Mitra, and S. R. Bhadra Chaudhuri, "An effective SAR reduction technique of a compact meander line antenna for wearable applications," Progress In Electromagnetics Research M, Vol. 55, 143-152, 2017.
doi:10.2528/PIERM16121501 Google Scholar

23. Zhong, J., A. Kiourti, T. Sebastian, and Y. Bayram J. L. Volakis, "Conformal load-bearing spiral antenna on conductive textile threads," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 230-233, 2017.
doi:10.1109/LAWP.2016.2570807 Google Scholar

24. Wang, K. and J. Li, "Jeans textile antenna for smart wearable antenna," 2018 12th International Symposium on Antennas, Propagation and EM Theory (ISAPE), 1-3, Hangzhou, China, 2018. Google Scholar

25. Wang, M., et al. "Investigation of SAR reduction using flexible antenna with metamaterial structure in wireless body area network," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 6, 3076-3086, Jun. 2018.
doi:10.1109/TAP.2018.2820733 Google Scholar

26. Pei, R., M. Leach, E. G. Lim, Z. Wang, J. Wang, and Y. Huang, "A belt antenna design with textile aritificial magnetic conductor reflector," 2019 IEEE MTT-S International Wireless Symposium (IWS), 1-3, Guangzhou, China, 2019. Google Scholar

27. Seimeni, M. A., A. Tsolis, A. A. Alexandridis, and St. Pantelopoulos, "Mitigation of end-user’s exposure to EMF of wearable antennas," Proceedings of the 14th Conference on Antennas & Propagation (LAPC2018), 5 pages, Loughborough, UK, Nov. 12–13, 2018. Google Scholar

28. Seimeni, M. A., A. Tsolis, A. A. Alexandridis, and S. A. Pantelopoulos, "The effects of ground-plane of a textile higher mode microstrip patch antenna on SAR," 2020 International Workshop on Antenna Technology (iWAT), 1-4, Bucharest, Romania, 2020. Google Scholar

29. CST Studio Suite, URL: https://www.3ds.com/products-services/simulia/products/cst-studio-suite/solvers/.. Google Scholar

30. Gabriel, C., "Compilation of the dielectric properties of body tissues at RF and microwave frequencies," Brooks Air-Force Base, report No. AL/OE-TR-1996-0037. Google Scholar

31., URL: http://niremf.ifac.cnr.it/tissprop/htmlclie/htmlclie.php#inizio, accessed May 21st, 2020. Google Scholar

32. Yilmaz, T., R. Foster, and Y. Hao, "Broadband tissue mimicking phantoms and a patch resonator for evaluating noninvasive monitoring of blood glucose levels," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 6, 3064-3075, Jun. 2014.
doi:10.1109/TAP.2014.2313139 Google Scholar

33. Castello-Palacios, S., A. Valles-Lluch, C. Garcia-Pardo, A. Fornes-Leal, and N. Cardona, "Formulas for easy-to-prepare tailored phantoms at 2.4 GHz ISM band," 2017 11th International Symposium on Medical Information and Communication Technology (ISMICT), Vol. 27, No. 31, Lisbon, 2017. Google Scholar

34. Groumpas, E., M. Koutsoupidou, I. S. Karanasiou, C. Papageorgiou, and N. Uzunoglu, "Real-time passive brain monitoring system using near-field microwave radiometry," IEEE Trans. Biomed. Eng., Vol. 67, No. 1, 158-165, 2020.
doi:10.1109/TBME.2019.2909994 Google Scholar

35. Mobashsher, A. T. and A. M. Abbosh, "Artificial human phantoms: Human proxy in testing microwave apparatuses that have electromagnetic interaction with the human body," IEEE Microwave Magazine, Vol. 16, No. 6, 42-62, Jul. 2015.
doi:10.1109/MMM.2015.2419772 Google Scholar

36. Tsolis, A., A. Paraskevopoulos, A. A. Alexandridis, W. G. Whittow, A. Chauraya, and J. C. Vardaxoglou, "Design, realisation and evaluation of a liquid hollow torso phantom appropriate for wearable antenna assessment," IET Microwaves, Antennas & Propagation, Vol. 11, No. 9, 1308-1316, 2017.
doi:10.1049/iet-map.2016.0235 Google Scholar

37. Zervos, T., A. A. Alexandridis, V. V. Petrovic, et al. "Mobile phone antenna performance and power absorption in terms of handset size and distance from user’s head," Wireless Pers. Commun., Vol. 33, 109-120, 2005.
doi:10.1007/s11277-005-7223-6 Google Scholar

Dr. Maria A. Seimeni

Dr. Aris Tsolis

Dr. Antonis A. Alexandridis

Dr. Stelios A. Pantelopoulos