In this paper, the performance of circularly polarized (CP) adaptive sub-arrays integrated into 5G laptop device is investigated in the presence of a whole-body human phantom model. In addition, the radiation effect of the steered beam patterns has been analyzed by calculating the specific absorption rate distribution and temperature rise. In this target, a single-feed CP antenna element has been firstly designed to resonate at 28 GHz with high realized gain and radiation efficiency. Then, 4 sub-arrays have been constructed in a rectangular configuration with four-elements for each sub-array. To let the study more realistic, a complete human model is considered to investigate the radiation effects. The measured reflection coefficient and realized gain results of the designed antenna element are found to be -30 dB and 7.82 dB, respectively, in the assigned frequency band. Likewise, the antennas sub-arrays have approximately kept the same impedance matching attitude with high insertion loss of -22 dB and a realized gain and radiation efficiency of 16.85 dB and 86%, respectively, on average. Furthermore, the sub-arrays scan patterns and coverage efficiency has been studied considering the existence of the human body in different scenarios. Regarding the RF exposure, the results show that the resultant maximum values of specific absorption rate and power density do not exceed 1.52 W/Kg and 3.5 W/m2, respectively, whereas, the maximum exposure temperature in such a case is less than 2.8°C after 30 minutes and decreases to 0.5°C after a penetration depth of 3 mm which reflects the possibility of safe use.
2. Accessed: Jan. 2021, [Online], , Available: https://www.delltech-nologies.com/enus/latitude/latitude-9510-coming-soon.htm.
3. Accessed: Jan. 2021, [Online], , Available: https://www8.hp.com/us/en/laptops/2-in-1s/elitedragonfly-convertible.html.
4. Accessed: Jan. 2021, [Online], , Available: https://www.lenovo.com/gb/en/laptops/yoga/yoga-cseries/Lenovo-Yoga-5G-p/88YGC801370.
5. Accessed: Jan. 2021, [Online], , Available: https://news.itu.int/wrc-19-agrees-to-identify-newfrequency-bands-for-5g/.
6. Naqvi, A. H. and S. Lim, "Review of recent phased arrays for millimeter-wave wireless communication," MDPI Sensors (Basel), Vol. 18, No. 10, 1-31, Oct. 2018.
7. Mahmoud, K. R. and A. M. Montaser, "Optimised 4×4 millimetre-wave antenna array with DGS using hybrid ECFO-NM algorithm for 5G mobile networks," IET Microw., Antennas Propag., Vol. 11, No. 11, 1516-1523, Aug. 2017.
8. Mahmoud, K. R. and A. M. Montaser, "Design of compact mm-wave tunable filtenna using capacitor loaded trapezoid slots in ground plane for 5G router applications," IEEE Access, Vol. 8, 27715-27723, 2020.
9. Balanis, C. A., Antenna Theory: Analysis and Design, John Wiley & Sons, 2016.
10. Hesari, S. S. and J. Bornemann, "Wideband circularly polarized substrate integrated waveguide endfire antenna system with high gain," IEEE Antennas Wireless Propag. Lett., Vol. 16, 2262-2265, 2017.
11. Hussain, N., M.-J. Jeong, J. Park, and N. Kim, "A broadband circularly polarized Fabry Perot resonant antenna using a single-layered PRS for 5G MIMO applications," IEEE Access, Vol. 7, 42897-42907, 2019.
12. Lin, Q. W., H. Wong, X. Y. Zhang, and H. W. Lai, "Printed meandering probe-fed circularly polarized patch antenna with wide bandwidth," IEEE Antennas Wireless Propag. Lett., Vol. 13, 654-657, 2014.
13. Hussain, N., M. Jeong, A. Abbas, T. Kim, and N. Kim, "A metasurface-based low-profile wideband circularly polarized patch antenna for 5G millimeter-wave systems," IEEE Access, Vol. 8, 22127-22135, 2020.
14. Mahmoud, K. R. and A. M. Montaser, "Synthesis of multi-polarised upside conical frustum array antenna for 5G mm-wave base station at 28/38 GHz," IET Microwave Antennas Propag., Vol. 12, No. 9, 1559-1569, Jul. 2018.
15. Accessed: Jan. 2021, [Online], , Available: https://www.micro-wavejournal.com/articles/27830-ibmand-ericsson-announce-5g-mmwave-phase-array-antenna-module.
16. Mahmoud, K. R. and A. M. Montaser, "Performance of tri-band multi polarized array antenna for 5G mobile base station adopting polarization and directivity control," IEEE Access, Vol. 6, 8682-8694, 2018.
17. Xu, B., et al., "Power density measurements at 15GHz for RF EMF compliance assessments of 5G user equipment," IEEE Trans. Antennas Propag., Vol. 65, No. 12, 6584-6595, Dec. 2017.
18. Colombi, D., B. Thors, C. T¨ornevik, and Q. Balzano, "RF energy absorption by biological tissues in close proximity to millimeter-wave 5G wireless equipment," IEEE Access, Vol. 6, 4974-4981, 2018.
19. Xu, B., M. Gustafsson, S. Shi, K. Zhao, Z. Ying, and S. He, "Radio frequency exposure compliance of multiple antennas for cellular equipment based on semidefinite relaxation," IEEE Trans. Electromagn. Compat., Vol. 61, No. 2, 327-336, Apr. 2019.
20. Colombi, D., B. Thors, and C. Tornevik, "Implications of EMF exposure limits on output power levels for 5G devices above 6 GHz," IEEE Antennas Wireless Propag. Lett., Vol. 14, 1247-1249, 2015.
21. Zhao, K., Z. Ying, and S. He, "EMF exposure study concerning mmWave phased array in mobile devices for 5G communication," IEEE Antennas Wireless Propag. Lett., Vol. 15, 1132-1135, 2016.
22. He, W., B. Xu, M. Gustafsson, Z. Ying, and S. He, "RF compliance study of temperature elevation in human head model around 28 GHz for 5G user equipment application: Simulation analysis," IEEE Access, Vol. 6, 830-838, 2018.
23. Thors, B., D. Colombi, Z. Ying, T. Bolin, and C. Tornevik, "Exposure to RF EMF from array antennas in 5G mobile communication equipment," IEEE Access, Vol. 4, 7469-7478, 2016.
24. Mahmoud, K. R. and A. M. Montaser, "Design of dual-band circularly polarised array antenna package for 5G mobile terminals with beam-steering capabilities," IET Microwave Antennas Propag., Vol. 12, No. 1, 29-39, 2018.
25. Hamed, T. and M. Maqsood, "SAR calculation & temperature response of human body exposure to electromagnetic radiations at 28, 40 and 60 GHz mmWave frequencies," Progress In Electromagnetics Research M, Vol. 73, 47-59, 2018.
26. 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, Vol. 3, No. 2, 237-247, 2011.
27. International Commission on Non-Ionizing Radiation Protection, "Guidelines for limiting exposure to electromagnetic fields (100 kHz to 300 GHz)," Health Physics, Vol. 118, No. 5, 483-524, 2020.
28. IEEE Standards Coordinating Committee, 28, "IEEE standard for safety levels with respect to human exposure to electric, magnetic, and electromagnetic fields, 0 Hz to 300 GHz," IEEE C95.1TM-(2019), 1-310, 2019.
29. Wu, T., T. S. Rappaport, and C. M. Collins, "Safe for generations to come: Considerations of safety for millimeter waves in wireless communications," IEEE Microwave Mag., Vol. 16, No. 2, 65-84, Mar. 2015.
30. Shrivastava, P. and T. R. Rao, "Investigations of SAR distributions and temperature elevation on human body at 60GHz with corrugated antipodal linear tapered slot antenna," Progress In Electromagnetics Research M, Vol. 59, 111-121, 2017.
31. Zhang, W.-X., J. Wang, R. Tao, H.-L. Peng, G. Guo, and J.-F. Mao, "A simplified model of specific absorption rate calculation for laptop mounted equipment in near proximity to human torso," Journal of Electromagnetic Waves and Applications, Vol. 26, 757-769, 2012.
32. Ahmed, M. I., M. F. Ahmed, and A. H. A. Shaalan, "SAR calculations of novel textile dual-layer UWB lotus antenna for astronauts spacesuit," Progress In Electromagnetics Research C, Vol. 82, 135-144, 2018.
33. Montaser, A. M., K. Mahmoud, and H. A. Elmikati, "An interaction study between PIFAs handset antenna and a human hand-head in personal communications," Progress In Electromagnetics Research B, Vol. 37, 21-42, 2012.
34. Kong, L.-Y., J. Wang, and W.-Y. Yin, "A novel dielectric conformal FDTD method for computing SAR distribution of the human body in a metallic cabin illuminated by an intentional electromagnetic pulse (IEMP)," Progress In Electromagnetics Research, Vol. 126, 355-373, 2012.
35. 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, No. 9, 1073-1080, 2011.
36. Azim, R., M. T. Islam, and N. Misran, "Ground modified double-sided printed compact UWB antenna," Electronics Letters, Vol. 47, No. 1, 9-11, 2011.
37. Nguyen, N. L., "Gain enhancement in MIMO antennas using defected ground structure," Progress In Electromagnetics Research M, Vol. 87, 127-136, 2019.
38. Accessed: Oct. 2019, [Online], , Available: https://itis.swiss/virtual-population/virtual-population/overview/.
39. Accessed: Dec. 2019, [Online], , Available: https://www.3ds.com/products-services/simulia/products/cst-studio-suite/.
40. Stephen, J. P. and D. J. Hemanth, "An investigation on specific absorption rate reduction materials with human tissue cube for biomedical applications," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 29, No. 12, 1-19, 2019.
41. Islam, M. T., M. R. I. Faruque, and N. Misran, "Reduction of specific absorption rate (SAR) in the human head with ferrite material and metamaterial," Progress In Electromagnetics Research C, Vol. 9, 47-58, 2009.
42. Montgomery, M. T., M. C. Frank, P. A. Tornatta, Jr., M. W. Kishler, and L. Chen, Methods for reducing near-field radiation and specific absorption rate (SAR) values in communications devices, U.S. Patent 8,344,956, issued January 1, 2013.
43. Nevermann, P., System and method for reducing SAR values, U.S. Patent 7,146,139, issued December 5, 2006.