A compact wideband planar quasi-Yagi antenna is proposed. The antenna consists of a symmetrical dipole connecting with two microstrip elements and can be directly integrated with differential circuits. The return loss, radiation pattern and gain over the whole operational frequency band have been analyzed. The operation principle is also discussed. It is shown that the impedance bandwidth of the antenna is from 2.19GHz to 5.65GHz, which is about 88.3%. Stable quasi-directional radiation patterns with an average gain about 4.8dBi can be achieved. Due to its performance, the antenna can be a good candidate for ambient RF energy harvesting applications.