This paper presents a novel microstrip-fed dual-band monopole antenna that is compact, low-profile, and suitable for WiMAX and WLAN applications. The antenna uses three strips joined together to create a U-shape, with the ground included to generate two resonances in the monopole antenna. The implementation of the three strips in the U-shaped monopole antenna significantly reduced its overall size significantly. Through simulation using the HFSS software, the antenna successfully achieved the desired resonant modes within specific frequency ranges suitable for WiMAX and WLAN applications. In addition, the antenna attained the desired impedance bandwidth at the resonant frequencies, enabling efficient performance within these frequency bands.