A circularly polarized broadband antenna with an L-shaped feed probe is presented. An L-shaped slot and a rectangular slot have been installed in this structure to enhance the 3-dB bandwidth in axial ratio. Also, a triangular slot have been installed at the edge of the slot to enhance the broadband characteristics in input impedance. This structure shows -10dB S11 characteristics of 65% and an -3dB axial ratio of 75%. The radiation patterns at different frequencies also show a good agreement between simulation and measurement as in S11 and axial ratio characteristics.