Patent ID: 8917216

Claim:
An antenna device comprising: a feeding line including a first conductor and a second conductor; and an antenna element comprising a conductive flat plate in which a slot is formed, wherein said antenna element is divided into an antenna pattern portion and a ground pattern portion via said slit, wherein the first conductor of said feeding line is connected to said antenna pattern portion, and the second conductor of said feeding line is connected to said ground pattern portion, wherein said conductive flat plate has first and second sides opposite to each other in a state where a center line extending in a predetermined direction is sandwiched therebetween, and a third side connecting the first and the second sides, wherein said slit is configured with: a first slit portion disposed so as to apart from the center line toward the first side by a first predetermined spacing; a second slit portion disposed so as to apart from the center line toward the second side by a second predetermined spacing; a third slit portion coupling the first slit portion with the second slit portion; and a cutting portion coupling the third slit portion with the third side.