In this research, a complex wideband antenna with different applications in wireless communication devices is proposed. The proposed wideband antenna resonates at different four frequencies, which include the wireless devices band, an Ultra-Wideband (UWB), and an X-band. This rectangle-shaped antenna with additional stub antennas has FR4 material used as a substrate with dimensions of (26 × 40 × 1.6 mm3). The resulting resonant frequencies cover Wireless Local-Area Network (WLAN) at 2 GHz and 5.3 GHz, Multiple Input Multiple Output (MIMO) at 6.7 GHz, and X-band at 8.7 GHz. The implementation of Defected Ground Structure (DGS) facilitates the reduction in size and increase in antenna performance, and by using the additional stubs, it provides a multi-sharpened band. It has an omnidirectional radiation pattern. Simulation results show that the proposed antenna provides a wide range of frequencies (4-9 GHz).