In this paper, a planar monopole antenna with variable frequency band-notch characteristic for ultrawideband applications is presented. The proposed antenna comprises a radiating rectangular patch and a truncated ground plane. Using two L-shaped strips on the top edge of the ground plane, antenna with ultra wide-band characteristic is provided, and in order to achieve notched band frequencies, two L-shaped slits are embedded on the ground plane. The designed antenna has a stop-band of 5 to 5.9 GHz while maintaining wideband performance from 3.1 to 10.6 GHz with VSWR < 2.