Abstract: A novel planar end-fire circularly polarized antenna having a wide bandwidth is proposed, which is based on a compact combination of a pair of complementary Yagi arrays that produce orthogonal polarization and common drive element.In order to improve the narrow working bandwidth of the vertically polarized Yagi array, A set of symmetric slits are introduced to cut each director of the vertically polarized and obtain a broad axial ratio bandwidth.A coupled microstrip line is introduced between the common drive element and the first director to improve the impedance bandwidth. At the same time, a microstrip line transition is introduced between the common drive element and the strip dipole of horizontally polarized director to further improve the antenna performance. The structure of the antenna were simulated and optimized by the HFSS software.The overall size of proposed antenna is 65 mm×65 mm×0.8 mm,and simulation results S₁₁＜-10 dB bandwidth of the antenna is 4.59-5.22 GHz（13.0%）,a 3 dB axial ratio bandwidth of the antenna is 4.58-5.19 GHz（12.5%）.