In the proposed paper, a rectangular monopole antenna with defected ground plane for UWB application is analyzed and experimentally studied. It is found that by making a slot on the ground plane return loss characteristic is improved. From experimental results, the measured impedance bandwidth of the fabricated structure covers a frequency band from 3 to 11 GHz with the central frequency at 6.9 GHz. Above analysis is done using commercially available CST Microwave Studio 2011 software and with optimized result it is fabricated on FR4 substrate having permittivity of 4.4 and thickness 1.6mm. Comparisons of simulated and experimental results were also done. The antenna exhibits Omni directional radiation pattern with <2 dBi gain for entire bandwidth are presented. © 2011 IEEE.