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International Journal of Antennas and Propagation
Volume 2013 (2013), Article ID 837643, 8 pages
http://dx.doi.org/10.1155/2013/837643
Research Article

Design of a Compact MIMO Antenna Using Coupled Feed for LTE Mobile Applications

Department of Electronics and Communications Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Republic of Korea

Received 10 September 2012; Revised 31 December 2012; Accepted 1 January 2013

Academic Editor: Hon Tat Hui

Copyright © 2013 Xing Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A compact multi-input multi-output (MIMO) antenna with a coupled feed structure for 4th generation (4G) handsets is proposed for operation in long-term evolution (LTE) band 13 (0.746 GHz–0.787 GHz). The MIMO antenna consists of two symmetrically distributed identical antenna elements. The size of each element is limited to 20 mm × 10 mm × 5 mm (  mm at 0.765 GHz), and the separation between different elements is minimized to 15 mm. Each antenna element contains a Z-shaped coupled feed strip and a simple folded monopole-type radiating element. The simple folded radiating element supports two monopole modes (first order) excited at adjacent frequencies to achieve broadband performance. The coupled feed strip effectively modifies impedance matching and maintains good isolation. The proposed antenna has a 6 dB return loss bandwidth of 55 MHz (0.735 GHz–0.79 GHz) and isolation above 12 dB without the use of an additional isolation enhancement element. Moreover, the envelope correlation coefficient (ECC) is maintained below 0.5 over the designed frequency band.