This document describes the design of a compact multiple-input multiple-output (MIMO) antenna array for wireless local area network (WLAN) applications. It presents a pattern diversity technique using printed Yagi-Uda antennas arranged in a triangular configuration to achieve orthogonal radiation patterns and reduce mutual coupling. Each Yagi-Uda antenna is designed on an FR4 substrate with a parasitic strip director and integrated balun. A 3-antenna array exhibits mutual coupling below -20 dB and bandwidth from 4.8-6.2 GHz covering the 5 GHz WLAN band with low cost and compact size suitable for indoor use.