An antenna structure according to an embodiment of the present disclosure includes a dielectric layer, and an antenna unit disposed on a top surface of the dielectric layer. The antenna unit includes a radiator including convex portions and concave portions, a transmission line including a first transmission line and a second transmission line that extend in different directions to be connected to the radiator, and a parasitic element disposed to be adjacent to the transmission line and electrically and physically separated from the transmission line and the radiator. A length of the parasitic element in an extension direction of the transmission line is from 45% to 70% of a half wavelength (λ/2) at a maximum resonance frequency from the antenna unit.