UWB Rectangular DRA Integrated with Reconfigurable Narrowband Antenna for Cognitive Radio Applications

A new ultra-wideband (UWB) dielectric resonator antenna (DRA) integrated with a reconfigurable narrowband (NB) antenna is designed and analyzed for cognitive radio (CR) applications. The UWB antenna consists of a rectangular dielectric resonator which is fed by a microstrip line. The NB antenna composes of a rectangular ring patch and three stubs which is fed by a microstrip line. The UWB and reconfigurable NB antennas provide 2:1 VSWR bandwidth from 3 to 11 GHz and from (3.25 to 3.7 GHz, 5.5 to 6.5 GHz, and 8 to 8.4 GHz), respectively. There is a reasonable isolation between the antennas. The narrowband recon?gurability is achieved by two p-i-n diode switches within the antenna structure. A prototype of the integrated antenna was fabricated and its performance was verified. The dimensions of the antenna are 65 mm x 40 mm x 6.5 mm. The antenna represents good radiation characteristics. Also, in order to reduce mutual coupling, the space between the ground planes is 10 mm.