Abstract: An antenna device includes a first antenna having a length corresponding to a first frequency, and arranged along a ground, a second antenna formed by a slot penetrating metal constituting the first antenna, and having a slot length corresponding to a second frequency higher than the first frequency, a first feeder wire for the first frequency, connected from the ground to the first antenna, a metal element for electromagnetic field coupling, arranged in a non-contact state relative to the second antenna, between the slot and the ground; and a second feeder wire for the second frequency, connected from the ground to the metal element.

Abstract: An antenna apparatus includes a ground substrate, a feeding point provided on the ground substrate, a first conductor device of which one end is electrically connected to the feeding point and which has a plate shape being parallel to the ground substrate, a second conductor device which is arranged between the first conductor device and the ground substrate, of which one end is electrically connected to the ground substrate, and which has a plate shape being parallel to the ground substrate and a connecting portion which electrically connects another end of the first conductor device and another end of the second conductor device to each other. A width of the first conductor device is wider than a width of the second conductor device. Lengths of the first conductor device and the second conductor device are ½ of a wavelength of a radio wave for operating the antenna apparatus.