Abstract: A simple, low cost and compact printed planer monopole Ultra-WideBand (UWB) antenna with single band notch characteristics is proposed. The antenna consists a semi-circular radiating patch, a modified ground plane and has a small size of 52.25x42x1.57 mm3 designed on a Rogers RT/Duroid 5870 substrate. A circular slot has introduced in the semicircular patch for achieving the stop band at 4 GHz C band frequency range. The antenna operates from 1.5-15 GHz with a single frequency band-stop performance of 3.58-4.92 GHz. The proposed antenna is successfully simulated, prototyped and measured. Fairly good agreements between the simulations and measurements have been achieved.