Integrated Ultrawideband/Narrowband Rectangular Dielectric Resonator Antenna for Cognitive Radio

An integrated ultrawideband (UWB) and narrowband (NB) rectangular dielectric resonator antenna (DRA) is presented. The proposed antenna consists of a UWB rectangular DRA excited by a bevel-shaped patch and an NB DRA excited by a strip. The measured results demonstrate that the UWB and NB antenna provides a 2:1 voltage standing wave ratio (VSWR) bandwidth for 2.4-12 and 2.3-4.5 GHz, respectively, with the same polarization. Moreover, two symmetrical short-circuited strips are introduced to improve the isolation between the two ports. This can be a suitable candidate for applications in cognitive radio, where the UWB antenna can be used for spectrum sensing and the NB antenna for communication operation.