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International Journal of Antennas and Propagation
Volume 2014 (2014), Article ID 638627, 7 pages
Research Article

Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications

1The ECE Department, American University of Beirut, Beirut 1107 2020, Lebanon
2The ECCE Department, Notre Dame University-Louaize, P.O. Box 72, Zouk Michael, Lebanon
3The Configurable Space Microsystems Innovations & Applications Center (COSMIAC), University of New Mexico, Albuquerque, NM 87131-0001, USA

Received 5 December 2013; Accepted 23 January 2014; Published 6 March 2014

Academic Editor: Mario Bkassiny

Copyright © 2014 A. H. Ramadan 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.


Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR-) based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein.