Modern wireless and mobile communication systems requires antenna which should have light weight, low profile, low cost, and easy to be integrated with RF devices. This demand is completed by microstrip antennas. This paper presents rectangular microstrip patch antenna for WLAN applications designed using IE3D software. The microstrip antenna is designed with dielectric substrate as Rogers RT/duroid 5880(tm) with ɛr = 2.2. This antenna will work on IEEE 802.11 WLAN 2.4 GHz band. The antenna is optimized to improve the performance measures like gain, return loss and efficiency. The IE3D result shows this antenna is suitable for WLAN applications.