volume | PIER Journals

Abstract

A wideband 10-port multiple input multiple output (MIMO) antenna array operated below 6 GHz for the fifth generation (5G) metal-frame smartphones is presented and discussed in this paper. The proposed MIMO antenna array element is composed of a microstrip line with a tuning stub and rectangular slot. The size of the rectangular slot is only 15 mm x 2 mm (0.211λ₀ x 0.028λ₀, and λ₀ is the wavelength with the resonance frequency of 4.2 GHz). U-shaped slots on the substrate are used to reduce the mutual coupling between the antenna elements. At the same time, in order to improve the radiation characteristics of the antenna arrays, narrow slits are etched in the metal-frame. The proposed antenna covers 3.3-5.5 GHz (S₁₁ < -6 dB), which is ultra-wide bandwidth for the 5G communications. The proposed MIMO antenna array is fabricated and measured. Results show that in the desired wide frequency band, the proposed antenna array can achieve desirable performances, including antenna isolation better than -13 dB with decoupling structures, efficiency, and envelope correlation coefficient (ECC)<0.06. Moreover, radiation pattern, calculated ergodic channel capacity, the effects of the user's hand effects and head specific absorption rate (SAR) are also given in the paper. Good agreement between measured and simulated results is obtained, which means that the proposed MIMO array is a good candidate for 5G metal-frame smartphone applications.

1. Hong, W., "Solving the 5G mobile antenna puzzle: Assessing future directions for the 5G mobile antenna paradigm shift," IEEE Microwave Magazine, Vol. 18, No. 7, 86-102, 2017.
doi:10.1109/MMM.2017.2740538 Google Scholar

2. Al-Dulaimi, Z., T. A. Elwi, and D. C. Atilla, "Design of a meander line monopole antenna array based hilbert-shaped reject band structure for MIMO applications," IETE Journal of Research, Vol. 66, 1-10, 2020.
doi:10.1080/03772063.2020.1743207 Google Scholar

3. Elwi, T. A., M. Noori, Y. Al-Naiemy, and E. S. Yahiea, "Conformal antenna array for MIMO applications," Journal of Electromagnetic Analysis and Applications, Vol. 6, No. 4, 43-50, 2014.
doi:10.4236/jemaa.2014.64007 Google Scholar

4. Alsaif, H., M. Usman, M. T. Chughtai, and J. Nasir, "Cross polarized 2 × 2 UWB-MIMO antenna system for 5G wireless applications," Progress In Electromagnetics Research M, Vol. 76, 157-166, 2018.
doi:10.2528/PIERM18101103 Google Scholar

5. Parchin, N. O., et al., "Eight-element dual-polarized MIMO slot antenna system for 5G smartphone applications," IEEE Access, Vol. 7, 15612-15622, 2019.
doi:10.1109/ACCESS.2019.2893112 Google Scholar

6. Wong, K. L. and J. Y. Lu, "3.6 GHz 10-antenna array for MIMO operation in the smartphone," Microwave and Optical Technology Letters, Vol. 57, No. 7, 1699-1704, 2015.
doi:10.1002/mop.29181 Google Scholar

7. Yang, M. and J. Zhou, "A broadband high-Isolation dual-polarized antenna for 5G application," Progress In Electromagnetics Research M, Vol. 85, 39-48, 2019.
doi:10.2528/PIERM19052003 Google Scholar

8. Wong, K. L., C. Y. Tsai, and J. Y. Lu, "Two asymmetrically mirrored gap-coupled loop antennas as a compact building block for eight-antenna MIMO array in the future smartphone," IEEE Transactions on Antennas and Propagation, Vol. 65, No. 4, 1765-1778, 2017.
doi:10.1109/TAP.2017.2670534 Google Scholar

9. Li, M. Y., Y. L. Ban, Z. Q. Xu, J. Guo, and Z. F. Yu, "Tri-polarized 12-antenna MIMO array for future 5G smartphone applications," IEEE Access, Vol. 6, 6160-6170, 2017. Google Scholar

10. Swain, B. R. and A. K. Sharma, "An investigation of dual-band dual-squarering (DSR) based microstrip antenna for WiFi/WLAN and 5G-NR wireless applications," Progress In Electromagnetics Research M, Vol. 86, 17-26, 2019.
doi:10.2528/PIERM19060501 Google Scholar

11. Zhang, X., Y. Li, W. Wang, and W. Shen, "Ultra-wideband 8-port MIMO antenna array for 5G metal-Frame smartphones," IEEE Access, Vol. 7, 72273-72282, 2019.
doi:10.1109/ACCESS.2019.2919622 Google Scholar

12. Huang, D., Z. Du, and Y. Wang, "Slot antenna array for fifth generation metal frame mobile phone applications," Int. J. RF Microw. Comput. Aided Eng., Vol. 29, No. 7, 1-9, 2019. Google Scholar

13. Li, Y., C. Sim, Y. Luo, and G. Yang, "Multiband 10-antenna array for sub-6GHz MIMO applications in 5G smartphones," IEEE Access, Vol. 6, 28041-28053, 2018.
doi:10.1109/ACCESS.2018.2838337 Google Scholar

14. Guo, J. L., L. Cui, C. Li, and B. H. Sun, "Side-edge frame printed eight-port dual-band antenna array for 5G smartphone applications," IEEE Trans. Antennas Propag., Vol. 66, No. 12, 7412-7417, 2018.
doi:10.1109/TAP.2018.2872130 Google Scholar

15. Stanley, M., Y. Huang, H. Wang, H. Zhou, Z. Tian, and Q. Xu, "A novel reconfigurable metal Rim integrated open slot antenna for octa-band smartphone applications," IEEE Transactions on Antennas and Propagation, Vol. 65, No. 7, 3352-3363, 2017.
doi:10.1109/TAP.2017.2700084 Google Scholar

16. Zhao, X., S. P. Yeo, and L. C. Ong, "Decoupling of inverted-F antennas with high-order modes of ground plane for 5G Mobile MIMO platform," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 9, 4485-4495, 2018.
doi:10.1109/TAP.2018.2851381 Google Scholar

17. Siu, L., H. Wong, and K. M. Luk, "Self-decoupled compact metal-frame LTE MIMO antennas for the smartphone," Microwave and Optical Technology Letters, Vol. 60, 1170-1179, 2018. Google Scholar

18. Kurvinen, J., A. Lehtovuori, J. Mai, C. Wang, and V. Viikari, "Metal-covered handset with LTE MIMO, Wi-Fi MIMO, and GPS antennas," Progress In Electromagnetics Research C, Vol. 80, 89-101, 2018.
doi:10.2528/PIERC17082303 Google Scholar

19. Arvind, K., C. Divya, and R. Singaravelu, "Design of a self-diplexing antenna using SIW technique with high isolation," AEU — International Journal of Electronics and Communications, Vol. 94, 386-391, 2018. Google Scholar

20. Kumar, A., D. Chaturvedi, M. Saravanakumar, et al. "SIW cavity-backed self-triplexing antenna with T-shaped slot," Asia-Pacific Microwave Conferenc (APMC), No. 6, 1588-1590, 2018.
doi:10.23919/APMC.2018.8617526 Google Scholar

21. Alnaiemy, Y., T. A. Elwi, and L. Nagy, "Mutual coupling reduction in patch antenna array based on EBG structure for MIMO applications," Periodica Polytechnica Electrical Engineering and Computer Science, Vol. 1, No. 4, 1-11, 2019. Google Scholar

22. Wong, K. L., B. W. Lin, and W. Y. Li, "Dual-band dual inverted-F/loop antennas as a compact decoupled building block for forming eight 3.5/5.8-GHz MIMO antennas in the future smartphone," Microwave and Optical Technology Letters, Vol. 59, No. 11, 2715-2721, 2017.
doi:10.1002/mop.30811 Google Scholar

23. Cui, L., J. Guo, Y. Liu, and C. Sim, "An 8-element dual-band MIMO antenna with decoupling stub for 5G smartphone applications," IEEE Antennas and Wireless Propagation Letters, Vol. 18, No. 10, 2095-2099, 2019.
doi:10.1109/LAWP.2019.2937851 Google Scholar

24. Abdullah, M., Y.-L. Ban, K. Kang, M.-Y. Li, and M. Amin, "Eight-element antenna array at 3.5 GHz for MIMO wireless application," Progress In Electromagnetics Research C, Vol. 78, 209-216, 2017.
doi:10.2528/PIERC17082308 Google Scholar

25. Ren, A., Y. Liu, and C. Sim, "A compact building block with two shared-aperture antennas for eight-antenna MIMO array in metal-rimmed smartphone," IEEE Transactions on Antennas and Propagation, Vol. 67, No. 10, 6430-6438, 2019.
doi:10.1109/TAP.2019.2920306 Google Scholar

26. Li, Y. D., C. Y. Sim, et al. "Metal-frame-integrated eight-element multiple-input multiple-output antenna array in the long term evolution bands 41/42/43 for fifth generation smartphones," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 29, No. 1, 1170-1179, 2018. Google Scholar

27. Chen, Q., et al., "Single ring slot-based antennas for metal-rimmed 4G/5G smartphones," IEEE Transactions on Antennas and Propagation, Vol. 67, No. 3, 1476-1487, 2019.
doi:10.1109/TAP.2018.2883686 Google Scholar

Dr. Peng Liu

Dr. Yufa Sun

Dr. Tao Liu

Dr. Qing Li

Dr. Xuefeng Wang