Patent ID: 7750755

Claim:
A transmission line transition for coupling electromagnetic energy comprising: a first dielectric substrate having a first portion; a waveguide tube including a hollow interior that has a longitudinal direction and a first cross-sectional area perpendicular to the longitudinal direction, one open end of the waveguide tube being attached to a first surface of the first dielectric substrate; a second dielectric substrate disposed on a second surface of the first dielectric substrate and having a second portion, the second portion and the first portion of the first dielectric substrate providing a dielectric waveguide having a first end short-circuited and a second end communicating with the hollow interior of the waveguide tube; a planar line located between the first and second dielectric substrates; an antenna located between the first and second dielectric substrates, the antenna being electrically connected to the planar line, the antenna being disposed in the dielectric waveguide to excite and to be excited by the waveguide tube, the antenna being spaced from the short-circuited end of the dielectric waveguide by a predetermined distance in the longitudinal direction; a first ground plane located between the first dielectric substrate and the waveguide tube; a second ground plane located between the first and second dielectric substrates; and a third ground plane located on the second dielectric substrate to provide the first short-circuited end of the dielectric waveguide, wherein the electromagnetic energy is coupled between the waveguide tube, the dielectric waveguide, and the planar line; each of the first and second dielectric substrates has a plurality of conductive members for electrically connecting the first, second and third ground planes; the dielectric waveguide is surrounded by the plurality of conductive members; the second ground plane has a first project portion projecting inwardly over the hollow interior of the waveguide tube by a first distance, the first project portion projecting from an edge of the plurality of the conductive members toward the antenna; the first ground plane has a second project portion projecting inwardly over the hollow interior of the waveguide tube by a second distance less than the first distance; and a terminal end of the antenna is spaced by a third distance relative to an edge of the first projection portion in a longitudinal direction of the antenna and is spaced by a fourth distance greater than the third distance relative to an edge of the second projection portion in the longitudinal direction of the antenna.