Patent ID: 7791546

Claim:
An antenna device operable at a first resonance frequency and a second resonance frequency, comprising: a folded element including an approach route portion extending from a feed portion to a folded portion via at least one angled portion, a return route portion extending from the folded portion to a ground portion in substantially parallel with the approach route portion, and a short-circuiting portion short-circuiting the approach and return route portions, a length of a route ranging from the feed portion to the ground portion via the folded portion being substantially equal to half a wavelength corresponding to the first resonance frequency, a distance between the feed portion and the ground portion being equal to or less than one fifth of the wavelength corresponding to the first resonance frequency; and an end-free element branching from the folded element between the feed portion and the angled portion, and including a free end, a length of a route ranging from the feed portion to the free end via a branching portion being substantially equal to one quarter of a wavelength corresponding to the second resonance frequency, wherein the feed portion is located close to one end of the antenna device, and the ground portion is located closer to the one end than the feed portion.