Antenna configurations for software defined radio and cognitive radio communication architecture

Cognitive radio is a new concept that utilizes the spectrum efficiently by shifting the frequency bands with time and availability. This puts a challenge on the antenna design to meet the demands of cognitive radio. This paper reviews the possible antenna configurations like wideband antennas, polarization and frequency reconfigurable antennas. Whilst there are many possible ways in which such systems could be configured, few possible antenna configurations are discussed and some design approaches are outlined.