This paper presents the simulation study of an ultra-wideband Dielectric Resonator Antenna (DRA). The simulation study has been carried out using CST Microwave Studio Software. The design procedure and simulation results of the rectangular dielectric resonator antenna and N-shaped dielectric resonator antenna are compared. The proposed antenna is designed on FR4 substrate with dielectric constant of = 4.6 and the overall size of the proposed DR antenna r 2 is 20 × 35 mm . The dielectric resonator of N- shape is only 5.12 mm thickness and a very low permittivity constant (10.2). The simulated DR antenna operates from 4.4 to 11.7 GHz to cover most of the existing wireless mobile standards. The radiation pattern is Omni-directional and has a simulated gain values up to 4 dB and the total efficiency of antenna is 99%. The results are showing acceptable performance in terms of return loss, VSWR, radiation pattern and realized gain. The results presented here may be useful in designing the portable personal communication device antennas and in analyzing the performance of these antennas for wireless communication.