Abstract: Disclosed is a substrate-integrated circularly polarized electromagnetic radiation structure. A plurality of connection points are provided between an upper metal radiation structure and a lower metal backplane; the upper metal radiation structure consists of a metal ring and two metal branches disposed within the metal ring; the metal branches are bent structures; the metal ring is a rectangular ring structure; the two metal branches are rotational symmetric by 180 degrees relative to a feeder center, and a serpentine structure composed of the two metal branches enables same to achieve circular polarization (comprising left-hand circular polarization and right-hand circular polarization) within broadband and to achieve beam directivity.