An antenna includes a first dielectric substrate and a first feeding element. The first dielectric substrate includes a first insulating layer, and a first radiation plate including a first opening that exposes an upper surface of the first insulating layer. The first feeding element is disposed in the first opening to penetrate the first insulating layer in a direction extending toward a lower surface of the first dielectric substrate. The first feeding element is insulated from the first radiation plate by the first insulating layer. The first feeding element includes a first conductive plate having an upper surface located on a same plane as an upper surface of the first radiation plate.