A dual-band bow-tie antenna for wireless local area network (WLAN) is designed at both the 2.4 and 5GHz (IEEE 802.11b/g and 802.11a) WLAN bands. The design procedure involves obtaining a full resonance frequency in the 2.4GHz band and then using Parasitic Elements to achieve a secondary resonance at the 5GHz band. The proposed antenna can provide two separate impedance bandwidths of 800MHz (about 30% centered at 2.4GHz) and 1100MHz (about 20% centered at 5.5GHz), making it easily cover the required bandwidths for WLAN operation in the 2.4GHz band (about 3.4% bandwidth required) and 5.2/5.8GHz bands (about 13% bandwidth required). The antenna structure has a compact dimension of 45mm × 35mm when printed on a substrate of dielectric with a thickness of 1.58mm and a relative permittivity of 2.2. The simulated radiation patterns are nearly omni-directional. The uniplanar nature, simple feeding technique and compact structure make it easy for modular design.