In this paper, CPW-fed slot antennas using loading metallic strips and a widened tuning stub (CPW-FSLW) which provides wideband operation on the flat, a Λ-shape reflector with horizontal plate that prevents the back radiation and provides the uni-directional radiation are investigated. We observe that the size and shape of the reflector have significant impact on the impedance matching and radiation patterns. By fabricating the CPW-FSLW on the Λ-shape reflector with horizontal plate structure, noticeable enhancements in both radiation pattern and bandwidth are achieved. The antennas are verified both through numerical simulations and also measurements of the experimental prototypes and these confirm the good performance antennas. It is found that the proposed antenna can deliver a measured impedance bandwidth of 64% from 1.6 to 3.1 GHz for VSWR ≤ 2. The antennas are designed to have wideband operation suitable for applications in GSM1800, GSM1900, PCS, IMT-2000 and WLAN bands.