Dual Port Cognitive Radio Antenna Using Tunable Band Pass Filter

In this paper a dual port microstrip antenna with tunable band pass filter is proposed for cognitive radio applications. In single port reconfigurable antennas for cognitive radio, sensing and communication is done simultaneously. This can lead to failure of real time communication, also it may induce interference to primary user, dual antenna system solves this problem. The proposed antenna consist of one UWB microstrip antenna for sensing the holes in spectrum and other is communication antenna. Communication antenna is made tunable by using varacter diode in 'G' shaped DMS(defected microstrip structure) filter integrated in feedline.The sensing antenna is having UWB bandwidth from 3.4 GHz to 13.2 GHz and efficiency of more than 80%. The narrowband antenna has dual and triple operating frequencies which is tunable in the range of This antenna as efficiency more than 70%. .