In this paper a circular microstrip patch antenna with Defected Ground Structure (DGS) has been designed and simulated for Ultra and Super Wide Band (UWB/SWB) applications by using the Computer Simulation Technology (CST). The aim of this work is to increase the bandwidth of an antenna by using (DGS). The total size of antenna is 25x30 mm2. This proposed antenna covers the frequency range of UWB and SWB for S11<-10dB was from 2.77 GHz to 30 GHz , this proposed antenna which gives a useful structure for modern wireless communication systems include point to point communication such as WVB (Wireless Video Broadcast), Satellite Communication and Radar Applications, WLAN applications “IEEE802.11a” in (5.12-5.825 GHz) and WiMAX system in (3.4–3.7 GHz) and for short range communication such as Biomedical applications.