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

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.

[1]  B.T. Quist,et al.  Optimal antenna pattern design for MIMO systems , 2007, 2007 IEEE Antennas and Propagation Society International Symposium.

[2]  Hiroyuki Arai,et al.  4×4 MIMO Prototype System and Measurement of Indoor Environment , 2005 .

[3]  Tetsuro Imai,et al.  Prediction of Propagation Characteristics in Tunnels Using Ray-Tracing Method , 2002 .

[4]  N. Honma,et al.  Proposal of compact MIMO terminal antenna employing Yagi-Uda array with common director elements , 2007, 2007 IEEE Antennas and Propagation Society International Symposium.

[5]  Yoshio Karasawa,et al.  An experiment on MIMO system having three orthogonal polarization diversity branches in multipath-rich environment , 2004, IEEE 60th Vehicular Technology Conference, 2004. VTC2004-Fall. 2004.

[6]  Beza Negash Getu,et al.  The MIMO cube - a compact MIMO antenna , 2005, IEEE Transactions on Wireless Communications.

[7]  John M. Cioffi,et al.  Spatio-temporal coding for wireless communication , 1998, IEEE Trans. Commun..

[8]  A. van Zelst.  Space division multiplexing algorithms , 2000 .

[9]  H. Nishimoto,et al.  Measurement-Based Performance Evaluation of MIMO Spatial Multiplexing in a Multipath-Rich Indoor Environment , 2007, IEEE Transactions on Antennas and Propagation.

[10]  M. J. Gans,et al.  On Limits of Wireless Communications in a Fading Environment when Using Multiple Antennas , 1998, Wirel. Pers. Commun..

[11]  Michael A. Jensen,et al.  Experimental characterization of the MIMO wireless channel: data acquisition and analysis , 2003, IEEE Trans. Wirel. Commun..