Patent ID: 7542000

Claim:
An apparatus comprising: a signal source, and an antenna for emitting an electromagnetic wave according to a signal from the signal source, wherein said antenna comprises a dielectric substrate, a planar antenna element disposed on the dielectric substrate, and a waveguide for propagating electromagnetic waves to or from the planar antenna element, wherein said antenna has a wavelength selected between λ/2 mm and λ mm, where λ is a wavelength of the electromagnetic wave passing through the dielectric substrate, wherein the waveguide comprises at least a center conductor and a grounded conductor extending along each other, and near a connection portion formed between the center conductor and the planar antenna element, there is provided a taper region in which a distance between mutually-facing edge portions of the grounded conductor and the center conductor increases approximately monotonically toward the planar antenna element, wherein a width W mm of the center conductor is constant, and wherein a distance d between the planar antenna element and the waveguide is 0 mm or more and 2 ⁢ 10.2 c ⁢ ⁢ λ mm or less.