Broad band antenna

The antenna apparatus for GHz frequency band, the antenna apparatus transmitting and receiving the electric wave having the wavelength λ, and wherein three orthogonal axes, and including the axis parallel to an edge of a ground plate and the axis along the surface of the ground plate being set,

• wherein a flat shaped antenna element, in which the length in the axis direction is less than λ/4 and the length in the axis direction is less than λ/4, is installed at the distance less than λ/4 from an edge of said ground plate in the axis direction, and
• wherein a flat shaped parasitic element having approximately the same shape and the same dimension as those of said flat shaped antenna element is installed at the distance less than λ/4 from said flat shaped antenna element, said flat shaped antenna element is connected conductively with the high-frequency power source, and the flat shaped parasitic element is connected conductively with the ground plate, respectively.

The antenna apparatus for GHz frequency band, the antenna apparatus transmitting and receiving the electric wave having the wavelength λ, and three orthogonal axes, and being set,

• wherein two flat shaped antenna elements, in which the length in the axis direction is less than λ/4 and the length in the axis direction is less than λ/4, are arranged so as to be brought into contact with surfaces in both sides of a substrate chip,
• wherein two flat shaped parasitic elements having approximately the same shape and the same dimension as those of said flat shaped antenna elements are installed at the distance less than λ/4 from each of said two flat shaped antenna elements, and
• wherein each of said two flat shaped antenna elements is elongated in the axis direction so as to be continuously provided with an extension portion facing to said flat shaped antenna element with a distance, thereby forming an enlarged flat shaped parasitic element.