A UWB antenna combined with a reconfigurable bandpass filter for cognitive radio applications

A single-port small-size antenna for cognitive radio (CR) applications is presented. The antenna is based on an ultra-wideband (UWB) design and has a reconfigurable bandpass filter integrated in its feed line. The UWB operation is required for the sensing task in a CR system. Upon activating the filter, the UWB frequency response is transformed into a tunable narrowband one, which is needed for the communication task.