A simple and compact directional dual-band semi-circular inverted-F antenna for wireless local area network applications is reported. Two pairs of semi-circular slots as well as a pair of arms are employed to generate the dual resonances in the 2.4-2.48 and 5.2-5.8 GHz bands. The measured results show that the proposed antenna can provide two 10 dB impedance bandwidths of 160 MHz (2.40-2.56 GHz) and 900 MHz (4.95-5.85 GHz). Nearly constant directivities (about 4.7 dBi) are observed in the lower band, while directivities in the upper band vary between 6.3 and 8.6 dBi.