Patent ID: 7652629

Claim:
An antenna device comprising: a ground plane having a first side; a plane conductor shaped like a polygon having a second side and a third side crossing each other, the plane conductor being arranged almost on a same plane as the ground conductor, the plane conductor being provided with a feed portion around the crossing between the second side and the third side, the plane conductor being arranged such that the second side faces the first side and the third side is almost perpendicular to the first side, and the plane conductor being configured to have a first resonant frequency determined by a first distance between the feed portion and an angle of the plane conductor diagonally opposite the feed portion, the first distance including a length of the second side; and a line conductor arranged almost on the same plane as the ground conductor, the line conductor being connected to the plane conductor around an end of the third side being opposite the feed portion, and the line conductor being configured to have a second resonant frequency which is lower than the first resonant frequency determined by a second distance between the feed portion and an end of the line conductor including lengths of the third side and the line conductor.