Wideband self-decoupled MIMO antenna element based on coupled-loop antenna for 5G smartphones

Abstract

A novel wideband self-decoupled loop-coupled antenna element is proposed for the fifth-generation (5G) multiple-input multiple-output (MIMO) smartphones. The proposed loop-coupled antenna element generates two resonance modes of 0.75 and 1 λ. With the help of these two resonance modes, a wide bandwidth is achieved. The self-decoupled performance is realized by loading the loop antenna element with coupled lines. The common/differential mode theory is used to analyze and guide the antenna design to clarify the self-decoupling principle. At the same time, miniaturization of the proposed antenna element is also studied. The antenna element provides good isolation and diversity/multiplexing performances over N77/N78/N79 bands. An 8-port MIMO antenna is constructed using the proposed antenna element. The MIMO antenna is simulated, manufactured, and tested to verify and evaluate the performance metrics, such as isolation, envelope correlation coefficient, efficiency, and spatial multiplexing efficiency. The test results are in good agreement with the simulated ones.

KEYWORDS:

• 5G communication
• common and differential modes
• coupled-loop antenna
• multiple-input multiple-output
• self-decoupling
• wideband smartphone antenna

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported in part by the National Natural Science Foundation of China under [grant number 62171362].

Notes on contributors

Bingyi Qian

Bingyi Qian received the B.S. degree in electronics and information engineering from Xidian University, Xi’an, China, in 2020, where he is currently pursuing the M.S. degree in electronics science and technology from Xi'an Jiaotong University, Xi'an. His current research interests include microstrip antenna design, mutual coupling reduction and 5G mobile antennas.

Xiaoyu Huang

Xiaoyu Huang received the B.S. degree in electrical engineering from Sichuan University, Sichuan, China, in 2020. He is currently pursuing the M.S. degree in electronics science and technology from Xi'an Jiaotong University. His current research interests include over-the-air (OTA) testing.

Xiaoming Chen

Xiaoming Chen (M'16, SM'19) received the B.Sc. degree in electrical engineering from Northwestern Polytechnical University, Xi’an, China, in 2006, and M.Sc. and PhD degrees in electrical engineering from Chalmers University of Technology, Gothenburg, Sweden, in 2007 and 2012, respectively. From 2013 to 2014, he was a postdoctoral researcher at the same University. From 2014 to 2017, he was with Qamcom Research & Technology AB, Gothenburg, Sweden, where he was involved in the EU H2020 5GPPP mmMAGIC project (on 5G millimeter-wave wireless access techniques). Since 2017, he has been a professor at Xi’an Jiaotong University, Xi’an, China. His research areas include 5G multi-antenna techniques, over-the-air (OTA) testing, and reverberation chambers. He has coauthored one book, two book chapter, more than 80 journal papers on these topics. Prof. Chen serves as an Associate Editor (AE) for the journal of IEEE Antennas and Wireless Propagation Letters (AWPL). He was also a Guest Editor of a Special Cluster on “5G/6G enabling antenna systems and associated testing technologies” in AWPL and a Special Issue on “Metrology for 5G Technologies” in the journal of IET Microwaves, Antennas & Propagation. He received the URSI (International Union of Radio Science) Young Scientist Awards in 2017 and 2018, and the IEEE outstanding AE awards in 2018, 2019 and 2020.

Le Chang

Le Chang received the B.S. degree in electronics and information engineering from Xidian University, Xi’an, China, in 2012, and the Ph.D. degree in electrical engineering from Tsinghua University, Beijing, China, in 2017. From 2017 to 2020, he was with the Antenna and RF Group, Huawei Device Ltd., Beijing, where he worked as a Senior Engineer. Since 2021, he has been a Special Appointed Researcher with Xi’an Jiaotong University, Xi’an. His current research interests include 5G mobile antennas, millimeter-wave antennas, and phased arrays.

Kunpeng Wei

Kunpeng Wei received the B.S. degree in electronic and information engineering from the Huazhong University of Science and Technology, Wuhan, China, in 2008 and the Ph.D. degree in electrical engineering from Tsinghua University, Beijing, China, in 2013. From 2013 to 2016, he was employed with the Radar Research Institute of Chinese Air Force Research Laboratory, Beijing, where he conducted research in the areas of phased-array antenna design and radar system design. Since 2016, he has been working for the Consumer Business Group, Huawei Device Ltd., Beijing, as a Smart-Phone Antenna Expert. He has authored more than 20 technical articles on omnidirectional antenna design and MIMO antenna design and holds more than eight Patent Cooperation Treaty (PCT)-patents as the first inventor. His current research interests include smart-phone antenna design, small size 5G antenna systems in terminal device, and millimeter-wave antenna array.

Azremi Abdullah Al-Hadi

Azremi Abdullah Al-Hadi (Senior Member, IEEE) was born in Michigan, USA, in August 26. He received the M.Sc. degree in communication engineering from Birmingham University, U.K., in 2004, and the D.Sc. degree in technology from Aalto University, Finland, in 2013. His current research interests include design and performance evaluation of multielement antennas, mobile terminal antennas and their user interactions, and wireless propagation. He is currently working as an Associate Professor and holds a position as the Dean of the School of Computer and Communication Engineering, Universiti Malaysia Perlis (UniMAP), where he has been with the School of Computer and Communication Engineering, since 2002. Dr. Al-Hadi is active in volunteering work with the IEEE Malaysia Section, acting as the Vice Chair of the IEEE Antenna Propagation/Microwave Theory Techniques/Electromagnetic Compatibility (AP/MTT/EMC) Malaysia Chapter, and the Counselor of the IEEE UniMAP Student Branch. He is a Chartered Engineer of the Institution of Engineering and Technology (IET), U.K., a member of the Board of Engineers Malaysia (BEM), Malaysia, and a Graduate Technologist of the Malaysia Board of Technologist (MBOT), Malaysia. He was a recipient of the Best Student Paper Award presented at the Fifth Loughborough Antennas and Propagation Conference (LAPC 2009) and the CST University Publication Award, in 2011.

Ahmed A. Kishk

Ahmed A. Kishk obtained his Ph.D. degrees in 1986 from the University of Manitoba, Canada. In 1986, he joined the University of Mississippi first as an Assistant Professor and then a Professor. Since 2011, he has been a Professor at Concordia University, Canada, as Tier 1 Canada Research Chair in Advanced Antenna Systems. He is a distinguished lecturer for the Antennas and Propagation Society (2013–2015). He was an Editor of Antennas & Propagation Magazine (1993–2014). He was an Editor-in-Chief of the ACES Journal from 1998 to 2001. He was a Guest Editor of the special issue on artificial magnetic conductors, soft/hard surfaces, and other complex surfaces, in the IEEE Transactions on Antennas and Propagation, 2005. He was the 2017 AP-S president. His research interest includes millimeter wave antennas, beamforming network, dielectric resonator antennas, microstrip antennas, EBG, etc. He has published over 340-refereed Journal articles and 450 conference papers. He is a co-author of four books and several book chapters and the editor of three books. Prof. Kishk won the 1995 and 2006 outstanding paper awards for the Applied Computational Electromagnetic Society Journal. He received the 1997 Outstanding Engineering Educator Award from Memphis section of the IEEE. He received the Outstanding Engineering Faculty Member of the Year in 1998 and 2009, Faculty research award for outstanding performance in research in 2001 and 2005. He received the Award of Distinguished Technical Communication for the entry of IEEE Antennas and Propagation Magazine, 2001. He also received The Valued Contribution Award for outstanding Invited Presentation from the Applied Computational Electromagnetic Society. He received the Microwave Theory and Techniques Society, Microwave Prize 2004 and 2013 Chen-To Tai Distinguished Educator Award of the IEEE Antennas and Propagation Society. He is a Fellow of IEEE since 1998, Fellow of Electromagnetic Academy, and a Fellow of the Applied Computational Electromagnetics Society (ACES).