Antenna Reconfiguration Techniques for Cognitive Radio: A Review

Abstract

As the usage of wireless communicative devices is multiplying day by day, the need for the occupiable radio spectrum is also increasing. The inefficiency in the exploration of available licensed radio spectrum has rerouted the focus to effectively use it against the increasing demand. One of the available methods is to implement Cognitive Radio (CR) technology. The Cognitive Radio uses 2 antennas at a time in order to scan and to communicate with the available spectrum. While an Ultrawideband (UWB) antenna scans the spectrum for unused bands of frequencies, Narrowband (NB) antennas communicate with these sensed unused bands. The technique of Reconfiguration in antennas is found to have a major role in implementing these UWB/NB antennas for CRs. Here in this paper, a survey is conducted on various reconfiguration techniques in antennas to build up a CR system. Each technique is studied in terms of the compactness, novelty, coverage of frequencies, and losses associated with the antenna. Finally, all the techniques are compared on the basis of their merits and demerits in this work.