Compact highly isolated dual-band 4-port MIMO antenna for sub-6 GHz applications

Abstract

In this work, a compact 4-element multiple-input multiple-output (MIMO) antenna system is presented for sub-6 GHz applications. A modified M-shaped strip is used to form each antenna element in the MIMO system. To improve performance, a rectangular-shaped area is etched on the opposite side of each element in the ground plane. The antenna size is 100 × 60 mm2. Most interestingly, the port isolation is improved by rotating the etched areas and the corresponding radiating elements. This one-of-a-kind approach aided in the development of a highly isolated MIMO antenna with a small footprint. The theory of characteristic modes (TCM) is used to analyze the behavior of rotating the etched areas in the ground of the antenna. The antenna provides significant port isolation above 20 dB, stable radiation patterns, and an outstanding ECC less than 0.01. The design is simple and compact, making it suitable for MIMO operation in handheld devices.

KEYWORDS:

• MIMO
• sub-6 GHz
• isolation
• 4G
• 5G

Disclosure statement

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

Additional information

Notes on contributors

Mohammad Ahmad Salamin

Mohammad Ahmad Salamin was born in Hebron, State of Palestine, in 1994. He received the B.Sc. degree in Communication and Electronics Engineering from Palestine Polytechnic University, Hebron, Palestine, in 2017. His research interests include multiple-input multiple-output (MIMO) antenna systems, millimeter-wave antennas, reconfigurable antennas, multi-band/wideband printed antennas, and other planar antennas for different wireless applications.

Asmaa Zugari

Asmaa Zugari received her BS degree in electronic engineering and MS degree in Telecommunications systems from Abdelmalek Essaâdi University, Tetuan, Morocco, in 2002 and 2004, respectively. She received the PhD in Telecommunications from Abdelmalek Essaâdi University, Tetuan, Morocco. The doctoral thesis was carried out as part of a collaboration between two laboratories: the Telecommunications & Information Systems Laboratory at Abdelmalek Essaâdi University and the LAPLACE Laboratory in the INPT, ENSEEIHT of the Paul Sabatier University, Toulouse, France. From 2014 to 2015, she was a Post-Doctoral in Hubert Curien Laboratory (LabHC), Jean Monnet University Saint-Etienne-France. Currently, she works as a professor in the faculty of sciences, Abdelmalek Essaâdi University. Her research interests include applied electromagnetism and numerical techniques for the design of microwave circuits and antennas.

Mohammad Alibakhshikenari

Dr. Mohammad Alibakhshikenari (Member, IEEE) was born in Mazandaran, Iran, in February 1988. He received the Ph.D. degree (Hons.) with European Label in electronics engineering from the University of Rome “Tor Vergata”, Italy, in February 2020. He was a Ph.D. Visiting Researcher with the Chalmers University of Technology, Sweden, in 2018. His training during the Ph.D. included a research stage in the Swedish company Gap Waves AB. He is currently with the Department of Signal Theory and Communications, Universidad Carlos III de Madrid (uc3m), Spain, as a Principal Investigator of the CONEXPlus Talent Training Program and Marie Sklodowska-Curie Actions. He is also a lecturer of the “electromagnetic fields” and “electromagnetic laboratory” in the department. His research interests include electromagnetic systems, antennas and wave-propagations, metamaterials and metasurfaces, synthetic aperture radars (SAR), multiple input multiple output (MIMO) systems, RFID tag antennas, substrate integrated waveguides (SIWs), impedance matching circuits, microwave components, millimeter-waves and terahertz integrated circuits, gap waveguide technology, beamforming matrix, and reconfigurable intelligent surfaces (RIS). The above research lines have produced more than 200 publications on international journals, presentations within international conferences, and book chapters with a total number of the citations more than 3100 and Hindex of 40. He is serving as an Associate Editor for IET Journal of Engineering and International Journal of Antennas and Propagation. He also acts as a referee in several highly reputed journals and international conferences.

Chan Hwang See

Chan Hwang See (Senior Member, IEEE) received the B.Eng. degree (Hons.) in electronic, telecommunication and computer engineering and the Ph.D. degree from the University of Bradford, U.K., in 2002 and 2007, respectively. He was a Senior Research Fellow with the Antennas and Applied Electromagnetics Research Group, University of Bradford. He was a Senior Lecturer (Programme Leader) in electrical and electronic engineering with the School of Engineering, University of Bolton, U.K. He is currently an Associate Professor and the Head of electrical engineering and mathematics with the School of Engineering and the Built Environment, Edinburgh Napier University, U.K. He is also a Chartered Engineer. He has published over 100 peer-reviewed journal articles in these research areas. He has co-authored one book and three book chapters. His research interests include wireless sensor network system design, computational electromagnetism, antennas, microwave circuits, and acoustic sensor design. He is a Fellow of the Institution of Engineering and Technology and the Higher Education Academy. He was a recipient of two Young Scientist awards from the International Union of Radio Science (URSI) and Asia-Pacific Radio Science Conference (AP-RASC), in 2008 and 2010, respectively. He was awarded the Certificate of Excellence for his successful knowledge transfer partnership (KTP) with Yorkshire Water, on the design and implementation of a wireless sensor system for sewerage infrastructure monitoring, in 2009. He is an Associate Editor for IEEE ACCESS and PeerJ Computer Science Journals.

Raed Abd-Alhameed

Raed Abd-Alhameed (Senior Member, IEEE) received the B.Sc. and M.Sc. degrees from the University of Basrah, Basrah, Iraq, in 1982 and 1985, respectively, and the Ph.D. degree from the University of Bradford, Bradford, U.K., in 1997, all in electrical engineering. Since September 2009, he has also been a Research Visitor at Wrexham Glyndwr University, Wrexham, U.K., covering the wireless and communications research areas. He is currently the Leader of radio frequency, propagation, sensor design, and signal processing, and lead the Communications Research Group for years within the School of Engineering and Informatics, Bradford University. He is also a Principal Investigator for several funded applications to EPSRCs and a leader of several successful knowledge transfer programmes (KTPs), such as with Arris (previously known as Pace plc), Yorkshire Water plc, Harvard Engineering plc, IETG Ltd., Seven Technologies Group, Emkay Ltd., and Two World Ltd. He is a Professor of electromagnetic and radio frequency engineering with the University of Bradford. He has also been a Co-Investigator in several funded research projects, including H2020 MARIE Sklodowska-CURIE ACTIONS: Innovative Training Networks “Secure Network Coding for Next Generation Mobile Small Cells 5G-US,” nonlinear and demodulation mechanisms in biological tissue (Department of Health, Mobile Telecommunications and Health Research Programme, and Assessment of the Potential Direct Effects of Cellular Phones on the Nervous System (EU: collaboration with six other major research organizations across Europe). He has long years of research experience in the areas of radio frequency, signal processing, propagations, antennas, and electromagnetic computational techniques, and has published more than 500 academic journals articles and conference papers, and has co-authored three books and several book chapters. His research interests include computational methods and optimizations, wireless and mobile communications, sensor design, EMC, beam steering antennas, energy-efficient PAs, and RF predistorter design applications.

Ernesto Limiti

Ernesto Limiti (Senior Member, IEEE) was a Full Professor of electronics with the Faculty of Engineering, University of Roma Tor Vergata, in 2002, and a Research Assistant and a Teaching Assistant, in 1991, where he has been an Associate Professor, since 1998. He represents the University of Roma Tor Vergata in the governing body of the MECSA (Microwave Engineering Center for Space Applications), an inter-University center among several Italian Universities. He has been elected to represent the Industrial Engineering Sector at the academic senate of the University for the term 2007–2010 and 2010–2013. He is actively involved in research activities with many research groups, both European and Italian, and is in tight collaborations with high-tech Italian, including SelexSI, Thales Alenia Space, Rheinmetall, Elettronica S.p.A., and Space Engineering, and foreign, including OMMIC, Siemens, and UMS companies. He contributed, as a Researcher and/or as a unit responsible person, to several National, such as PRIN MIUR, Madess CNR, and Agenzia Spaziale Italiana, and International, such as ESPRIT COSMIC, Manpower, Edge, Special Action MEPI, ESA, EUROPA, Korrigan, and RadioNet FP6 and FP7 projects. Regarding teaching activities, he teaches over his institutional duties in the frame of the corso di laurea magistrale in ingegneria elettronica, “elettronica per lo spazio” within the master's course in sistemi avanzati di comunicazione e navigazione satellitare. The following research lines have produced more than 250 publications on refereed international journals and presentations within international conferences. His research interests include three main lines, all of them belonging to the microwave and millimetre-wave electronics research area. He is a member of the Committee of the Ph.D. Program in telecommunications and microelectronics at the University of Roma Tor Vergata, tutoring an average of four Ph.D. candidates per year. He is actually the President of the Consortium “Advanced Research and Engineering for Space,” ARES, formed between the University and two companies. Further, he is actually the President of the Laurea and Laurea Magistrale degrees in electronic engineering with the University of Roma Tor Vergata. He acts as a referee of international journals of the microwave and millimetre wave electronics sector and is in the Steering Committee of international conferences and workshops.