Abstract
This paper presents the effect of the ground plane slots up on the bandwidth performance for the ultra-wideband (UWB) antenna. The reference antenna is microstrip feed line monopole antenna with a square radiator and a partial ground plane. Four different slots configurations (triangular, trapezoidal, rectangular and circular) have been inserted to the partial ground plane under the feed line to modify the reference antenna bandwidth characteristics. The effect of the single and multiple slots cases up on the bandwidth characteristics is investigated using CST-EM software package. The simulation results prove that the antenna bandwidth can be enhanced or has some reject bands based on the slots configurations and slots nu mbers.