An Integrated Frequency Reconfigurable Antenna for Cognitive Radio Application

A novel integrated antenna that consists of spectrum sensing and frequency reconfigurable antenna, printed on a single substrate is presented here. The integration of both antennas is based on the fact that reasonably large metallization area of UWB antenna can be used as a space for printing another narrowband antenna. Prominently, the second antenna should be placed on a region of large UWB antenna where there is less distribution of E field. The proposed antenna senses the spectrum over a wide frequency range from 2 GHz to 12 GHz via a U shape monopole having partial ground structure. After sensing the spectrum condition, the slot antenna with reconfigurable feeding structure can switch its operating bands among six narrowbands: 5.65 GHz, 3.6 GHz, 5 GHz, 2.94 GHz, 4.5 GHz, 2.15 GHz and two dual bands at 2 GHz, 5.48 GHz and 1.7 GHz, 5 GHz. In addition to this, the proposed antenna can also reconfigure its frequency in wide-bandwidth using two ground stubs. Since wide band response for spectrum sensing and each of eight frequency state works independently, therefore, there is no interference among various signals.