A single element circular slot aperture coupled Cylindrical Dielectric Resonator Antenna (CDRA) with a box shaped reflector is designed and presented. The simulated bandwidth achieved for the designed antenna is about 1.11 (5.32 GHz-5.44 GHz) while the measured bandwidth is about 1.8 (5.32 GHz-5.52 GHz). This method enhances the directivity of the CDRA upto 53 i.e from 5 dBi to 7.5 dBi. The analysis of the effects of changing the slot size, slot position and different parameters of the reflector to increase the directivity and to reduce the backlobe level has been carried out. The experimental results illustrate that the designed antenna works over 5 GHz band, therefore it can be used in WLAN application IEEE 802.11a. © 2013 IEEE.