Abstract
An integrated narrow/ultra-wideband antenna composite is proposed for use in cognitive radio applications. The proposed antenna consists of two slot antennas with individual feeds sharing the same substrate. The ultra-wideband (UWB) antenna covers the entire UWB band from 3.1GHz to 10.6GHz and is used for channel sensing. The integrated narrow band antenna operates at 8.2GHz to 9.4GHz communicate with other wireless devices. The two ports have a good isolation, which is better than -10dB. The design is suitable for cognitive radio applications where the UWB antenna is required for spectrum sensing, and where the narrowband antenna is used for reconfigurable operation, which can be tuned over a wide bandwidth by changing its dimensions of the isosceles triangular radiation patch.