Reducing Mutual Coupling of MIMO Antennas With Parasitic Elements for Mobile Terminals

• Published in: IEEE transactions on antennas and propagation Vol. 60; no. 2; pp. 473 - 481
• Main Authors: Zhengyi Li, Zhengwei Du, Takahashi, M., Saito, K., Ito, K.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2012; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna radiation patterns; Antennas; Channel capacity; Correlation; Couplings; Current distribution; Design engineering; Deterioration; Joining; MIMO; MIMO antennas; Mutual coupling; parasitic elements; Receiving antennas; Terminals
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2011.2173432

Mutual coupling is a critical problem in the design of MIMO antennas because it deteriorates the performance of MIMO systems, which not only affects the antenna efficiency but also influences the correlation. Therefore, in this paper, using parasitic elements to reduce mutual coupling is studied. By adding parasitic elements a double-coupling path is introduced and it can create a reverse coupling to reduce mutual coupling. As an example, a dual-slot-element antenna with parasitic monopoles for mobile terminals is described. The discussion on channel capacity shows that the antenna can be considered as a good candidate for MIMO systems. Furthermore, based on the study of current distributions, it is concluded that the technique is sensitive to relative positions between parasitic elements, and relative positions between active element and parasitic element. Finally, we also extend the technique to a tri-element antenna.