A planar Ultrawideband (UWB) integrated with multi narrowband cylindrical dielectric resonator antenna (CDRA) for cognitive radio (CR) application is addressed. In this communication the proposed design is composed of two different antennas with different feeding mechanisms. The first one is a modified planar hexagon (combination of hexagon with rectangular patch) as UWB radiator excited by coplanar waveguide (CPW) feed and the second represents a CDRA, behaving as narrowband radiator, excited by a slot coupled micro strip feed line. The UWB antenna ranges from 3.0GHz to 12GHz and the narrow band (NB) CDRA operating at three different resonance frequencies ranges from 5.1GHz (4.93–5.4)GHz, 6.3GHz (5.9–6.7)GHz and 9.76GHz (9.28–10.2) GHz respectively with reasonable isolation between them. The proposed design is quite fit for CR application where the UWB radiator is used for spectrum sensing and narrow band antenna for the sake of communication. In addition, the proposed antenna can be potentially used for WiMAX, C-band and X-band satellite link in first, second and third communication band respectively. The optimized antenna as a prototype was fabricated and all its relevant parameters were measured. The comparative results (simulation and measurement) reveal a good agreement.