A Low-Profile Dual-Polarized Directional Antenna for Enhancing Channel Capacity in Indoor MIMO Systems

Daisuke UCHIDA
Hiroyuki ARAI
Keizo CHO

IEICE TRANSACTIONS on Communications   Vol.E93-B    No.10    pp.2570-2577
Publication Date: 2010/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.2570
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Advanced Technologies in Antennas and Propagation in Conjunction with Main Topics of ISAP2009)
Category: Antennas
MIMO,  radiation pattern,  polarization,  channel capacity,  low-profile antenna,  

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The use of directional antenna and polarization diversity techniques has been reported to achieve good MIMO performance. Low-profile, small structures are required to configure the MIMO antenna with these techniques. First, we assume downlink transmission in indoor MIMO systems and present the design guidelines for the radiation pattern to obtain large channel capacity by the ray-tracing method. We then propose a uni-directional, dual-polarized MIMO antenna with a thickness of 0.24λ based on the design guidelines. The proposed antenna consists of dipole antennas mounted horizontally to the ground plane and cavity backed slot antennas for vertical polarization. We apply the proposed antenna to 2 2 MIMO transmission and demonstrate the effectiveness of channel capacity enhancement in an actual environment. The improvement factor is revealed to be +16.2% with place averaged value compared to sleeve antenna configuration.