A simple dual band coaxial fed microstrip patch antenna has been designed to meet the (IEEE 802.11n) standard (released Oct., 2009) for high speed Wireless Local Area Network (WLAN) to operate at (2.45 and 5.8 GHz). The position of the coaxial fed probe is chosen to provide the required matching for excitation of the dual resonance frequencies. The patch length is chosen to radiate at the lower frequency and with the help of a slot along the patch; the coupling provided resonance tuning for the higher frequency. The patch was designed, simulated, fabricated and measured. There was a very good agreement between the measured and the simulated results.