Patent ID: 7466267

Claim:
An antenna device, comprising: a dielectric substrate; a ground plane, which is formed on a surface of the dielectric substrate; a pair of antenna elements, which are flat and which have different resonant frequencies and which are formed on another surface of the dielectric substrate and which respectively have ends electrically connected to the ground plane; a feeding section for feeding power to each of the antenna elements; and a pair of transmission lines, which are connected respectively to the antenna elements and which carry out impedance conversion such that parts of the transmission lines which are connected to the antenna elements have impedances matching input impedances of the antenna elements, respectively, and such that part of the feeding section which is fed with the power has an impedance matching an impedance of the feeding section, wherein each antenna element includes first and second rectangular sections, the second rectangular sections being adjacent to the first rectangular sections, the first and second rectangular sections forming an L-shape, the second rectangular sections being electrically connected to the ground plane via through holes.