Abstract: A wide-beam circularly polarized antenna unit and a 1×4 antenna array are designed to realize one-dimensional wide-angle circular polarization scanning in this paper. Antenna unit consists of a single layer radiating patch and a dielectric substrate integrated waveguide (SIW) back cavity. The right-handed circular polarization is achieved by chamfering and cutting the U-groove on the radiating patch, andbroaden the beam is utilized by the SIW back cavity gap. At the same time, the SIW back cavity is used to reduce the mutual coupling between the array elements to realize wide-angle circular polarization scanning. A circular polarization scan characteristic that achieves a good wide angle range. The simulation and test results show that the antenna array has a scan angle from -53° to 57°, 3 dB beam width coverage from -76° to 79°, an axial ratio (AR) of less than 3 dB in the main beam scan range, and a smooth gain variation over the scan range. A circular polarization scan characteristic that achieves a good wide angle range.