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International Journal of Antennas and Propagation
Volume 2014, Article ID 825403, 13 pages
http://dx.doi.org/10.1155/2014/825403
Research Article

Spatial Spectrum-Based Imaging for UWB Through-the-Wall MIMO Arrays

College of Electronic Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073, China

Received 2 April 2014; Revised 23 June 2014; Accepted 28 June 2014; Published 21 July 2014

Academic Editor: Ahmed Shaharyar Khwaja

Copyright © 2014 Biying Lu 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

To keep the system complexity at a reasonable level and conform to the propagation demands, MIMO arrays are usually sparse in through-the-wall applications, which results in corrupted and gapped data. The corresponding imaging results are seriously affected by the high-level sidelobes. To solve this problem, a new imaging model for ultra-wideband (UWB) MIMO arrays is constructed via spatial spectrum theory in this paper. Based on the model, the characteristics of the spatial spectrum for the MIMO array and its effects on imaging are discussed. To improve the imaging quality, a through-the-wall imaging enhancement method is proposed via spatial spectrum estimation. Synthetic and experimental results show that, unlike the conventional amplitude weighting methods and nonlinear techniques, the proposed method can efficiently suppress sidelobes in the imagery, especially for the sparse MIMO array, and consequently improve the target image quality without degrading the mainlobe resolution. The proposed method has been successfully used in our real through-the-wall radar system.