Patent attributes
An antenna device includes a substrate having a ground conductor, an antenna conductor disposed approximately parallel with the ground conductor with an air layer or a dielectric layer, plural short-circuiting conductors that connect the antenna conductor to the ground conductor, and a feed conductor disposed in a vicinity of one of the plural short-circuiting conductors and that feeds the antenna conductor with power. When a wavelength of frequency used in the antenna device is represented by λ, an outer circumferential length of the slot is approximately 1λ to 2λ and a width of the slot is 0.005λ to 0.05λ, an interval between the plural short-circuiting conductors is shorter than or equal to λ/2, and a distance between the antenna conductor and the ground conductor is 0.005λ to 0.05λ.