An integrated antenna for cognitive radios

An integrated antenna utilizing uniplanar nature of coplanar wave guide with wide and narrow band characteristics for category-A cognitive radios is presented. The space between two tapering which forms the ultra-wideband antenna (UWBA), where the surface current is minimum, is effectively used for the integration of a narrow band antenna (NBA). The UWBA and NBA provide 2:1 VSWR bandwidths from 2.7GHz to 11GHz and 5.0 GHz to 5.5GHz, respectively with isolation better than 15dB. The radiation characteristics are suitable for cognitive radio systems, where a UWBA is used for spectrum sensing and NBA for communication.