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International Journal of Antennas and Propagation
Volume 2012, Article ID 609598, 10 pages
http://dx.doi.org/10.1155/2012/609598
Research Article

A Flexible Phased-MIMO Array Antenna with Transmit Beamforming

1The School of Communication and Information Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, China
2The State Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101, China

Received 15 November 2011; Revised 23 January 2012; Accepted 24 January 2012

Academic Editor: Hon Tat Hui

Copyright © 2012 Wen-Qin Wang and Huaizong Shao. 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

Although phased-array antennas have been widely employed in modern radars, the requirements of many emerging applications call for new more advanced array antennas. This paper proposes a flexible phased-array multiple-input multiple-output (MIMO) array antenna with transmit beamforming. This approach divides the transmit antenna array into multiple subarrays that are allowed to overlap each subarray coherently transmits a distinct waveform, which is orthogonal to the waveforms transmitted by other subarrays, at a distinct transmit frequency. That is, a small frequency increment is employed in each subarray. Each subarray forms a directional beam and all beams may be steered to different directions. The subarrays jointly offer flexible operating modes such as MIMO array which offers spatial diversity gain, phased-array which offers coherent directional gain and frequency diverse array which provides range-dependent beampattern. The system performance is examined by analyzing the transmit-receive beampatterns. The proposed approach is validated by extensive numerical simulation results.