To design a slot antenna intended to work at four bandwidth frequency groups, which meet the specifications of (DO,1xRTT-3G), (WiMAX-IEEE802.11e), (WiMAX-IEEE802.16m) and (Wi-Fi.802.11b,g, & n) communications. The slot in the proposed antenna taken the form of the character (Q) that was feed by step impedance micro strip line design open mouth ended. The surface current distribution at resonant frequencies and the effect of varying the dimensions of the parameters on impedance bandwidth had been studied carefully in this research to enhance the performance of resonant frequency.