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International Journal of Antennas and Propagation
Volume 2010 (2010), Article ID 596291, 18 pages
http://dx.doi.org/10.1155/2010/596291
Research Article

Compact Printed Arrays with Embedded Coupling Mitigation for Energy-Efficient Wireless Sensor Networking

Mobile Radio Communications Laboratory, National Technical University of Athens, 9 Heroon Polytechniou Sreet, Zographos Polytechnic Campus, 15773 Athens, Greece

Received 1 December 2009; Accepted 1 April 2010

Academic Editor: Hoi Shun Lui

Copyright © 2010 Constantine G. Kakoyiannis and Philip Constantinou. 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

Wireless sensors emerged as narrowband, resource-constrained devices to provide monitoring services over a wide life span. Future applications of sensor networks are multimedia-driven and include sensor mobility. Thus, sensors must combine small size, large bandwidth, and diversity capabilities. Compact arrays, offering transmit/receive diversity, suffer from strong mutual coupling (MC), which causes lower antenna efficiency, loss of bandwidth, and signal correlation. An efficient technique to reduce coupling in compact arrays is described herein: a defect was inserted in the ground plane (GNDP) area between each pair of elements. The defect disturbed the GNDP currents and offered multidecibel coupling suppression, bandwidth recovery, and reduction of in-band correlation. Minimal pattern distortion was estimated. Computational results were supported by measurements. The bandwidth of unloaded arrays degraded gracefully from 38% to 28% with decreasing interelement distance (0.25 𝜆 to 0.10 𝜆 ). Defect-loaded arrays exhibited active impedance bandwidths 37–45%, respectively. Measured coupling was reduced by 15–20 dB.