A printed rectangular monopole antenna fed by a tapered coplanar waveguide (CPW) with a band-notched characteristic is proposed for ultra wideband (UWB) applications. It is shown that the notched or rejected band with a wide operating bandwidth is obtained by embedding an E shape slot in the rectangular radiation patch and its parameters studied in detail. The notched band is controllable by adjusting the lengths, location and the width of the slot. With a compact size of 36 × 34 mm2, the proposed antenna showing omni-directional radiation patterns with a notched frequency band at 5 GHz is demonstrated, which is suitable for UWB applications.