An antenna structure, comprising: a metal box body, a first dielectric substrate and a second dielectric substrate stacked from the bottom to the top; the second dielectric substrate is provided with a parasitic patch on the upper surface, the first dielectric substrate is provided with a radiating patch on the upper surface, and the parasitic patch and the radiating patch are arranged opposite to each other; a third dielectric substrate is provided inside the metal box body; a Wilson power divider is provided on the third dielectric substrate; an SMA coaxial connector is provided on the side wall of the metal box body; the branch port of the Wilson power divider is electrically connected to the radiating patch, and the combined port is connected to the SMA coaxial connector to feed the external device to realize circular polarization wave radiation; a U-shaped slot is provided on the radiating patch. The antenna structure provided by the present invention has the advantages of simple structure, high gain and small volume.