Abstract:
The proposed antenna designed specifically for Cognitive radio applications consists of a circular monopole which is evolved into the C shaped slotted monopole by a systematic process. The evolution of antenna is detailed. The evolved geometry enhances the gain with still good value of bandwidth. This ultra-wideband sensing antenna covers the spectrum from 4.305 GHz -12.73 GHz [8.428GHz] with a gain of 5.47 dBi as against 10.56GHz bandwidth of plane circular monopole with a gain of 2.17 dBi. Simulated results are presented and find in good agreement with the expected results. This antenna with slight modification can also be used as UWB antenna working in the range of 3.1GHz to 10.6GHZ.

Keywords: Cognitive Radio, Frequency Reconfigurable, C shaped monopole, UWB Antenna