Patent ID: 7248224

Claim:
An antenna device comprising: a plate-shaped conductor; a radiating conductor that extends outward from an end portion of the plate-shaped conductor and has a length corresponding to a quarter wavelength of a first frequency; a strip-shaped slot portion that is formed by removing a part of the plate-shaped conductor extending inward from the vicinity of the end portion from which the radiating conductor extends and has a length corresponding to a quarter wavelength of a second frequency, the second frequency being different from the first frequency; and a feed portion that is disposed to be perpendicular to the slot portion and to cross over the slot portion and that feeds the same signals to the slot portion and the radiating conductor, wherein a polarization plane of a radiating electric field radiating from the radiating conductor and a polarization plane of a radiating electric field radiating from the slot portion are disposed to be perpendicular to each other.