JELE_V4_N4_RP5 Srithar A. E.D. Kanmani Ruby Journal on Electronics Engineering 2249 – 0760 4 4 25 36 Cognitive Radio, Ultra Wide Band, Narrowband, Antenna Cognitive radio is an inventive system to wireless technologies, in which radios are designed with an astonishing level of intelligence and agility. This handles the available spectrum in an expedient manner to avoid spectrum scarcity. The cognitive radio antenna consists of integrated wideband and narrow band antenna in same substrate which is taxing task. A UWB (Ultra Wide Band) antenna is pondered for the wide band operation which has the bandwidth of 7.5GHz respectively used for sensing vacant slots in the spectrum. Narrow band antenna and pattern Reconfigurable antenna are usually used for transmission of data through the vacant slots from the outcomes of sensing antenna. In this paper, the various cognitive radio antennas are investigated in tremendously. June – August 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=3199