Semi circular -semi hexagon microstrip antenna integrated with DRA for cognitive radio applications

An ultra-wideband (UWB) planar microstrip antenna integrated with a narrow-band cylindrical dielectric resonator antenna (DRA) is presented for cognitive radio applications. The proposed antenna is a combination of semicircular-semi hexagon shape microstrip patch, which is fed by coplanar waveguide (CPW). The dielectric resonator antenna (DRA) is cylindrical in shape excited by a microstrip slot fed on the rear side which shows a narrow band (NB) characteristics. The microstrip antenna provides a wide bandwidth operates from 2.58 GHz to 14 GHz. The DRA provides a narrow bandwidth operates from 10.07 GHz to 11.38 GHz. The UWB antenna is used for sensing the spectrum and the narrow-band DRA used for communication operation. A very good isolation between the two antenna ports (S₂₁ less than -15 dB) are also achieved. Compared to the existing designs the peak gain of the antenna is highly increased around 6.15 dB.