In this communication, a novel dual-circularly polarized (CP) antenna with both wide half-power beamwidth (HPBW) and wide axial-ratio beamwidth (ARBW) is proposed. Based on the septum circular polarizer, the principle about HPBW improvement of its Eθ and E components is extensively studied. It proves that the metal rings around the top surface could be used to enhance the low elevation gain and extend its HPBW of Eθ components. Subsequently, a set of slots is introduced on the waveguide to expand the HPBW of its Ecomponent. With these arrangements, both ARBW and HPBW parameters of the antenna are simultaneously widened while keeping wide impedance bandwidth as desired. In addition, the antenna element is constructed as the 1×8 phased array for wide-angle scanning in such a way that the array antenna can satisfactorily achieve a wide CP scanning range and stable radiation pattern. Finally, the proposed antenna is designed, fabricated, and measured. The results evidently reveal that the proposed element can simultaneously achieve 3-dB HPBW and 3-dB ARBW in the range of 130° in 3.8-4.2 GHz, and its inspired array can effectively achieve beam scanning from -60° to 60° in 3.9-4.2 GHz.