An antenna apparatus includes: a ground plane including first sides parallel to a first direction and second sides parallel to a second direction, on a plane formed in the first and second directions; a dielectric layer disposed on the ground plane in a third direction; an antenna patch overlapping the ground plane in the third direction; and vias connected to the ground plane and passing through at least a portion of the dielectric layer. Edges of the vias at least partially overlap the first sides of the ground plane in the third direction.