Reconfigurable Rotated-T Slot Antenna for Cognitive Radio Systems

A novel reconfigurable slot antenna for the upper ultra wideband frequency range is presented. The antenna can operate at any of eight adjacent sub-bands in the 6.0-10.6 GHz frequency band, and is configured by means of seven PIN diode switches. At each of its sub-bands, the antenna provides a nearly omnidirectional radiation pattern in the horizontal plane, with predominantly vertical polarization.