Abstract: A wide beam microstrip antenna with a metal ring patch as the main radiator has been proposed. A circularly polarized phased array antenna with wide-angle scanning performance was designed based on the antenna unit, which operates in the frequency range of 19~21GHz. The beam width of the antenna unit was widened by loading parasitic periodic circular metal patches. When the designed 8 × 8 array antenna beam is scanned within the range of ± 60 °, the gain only decreases by 3.5dB, which is greater than 18 dBic.