Vertical-transition structure

A vertical-transition structure comprising:

• a grounded coplanar waveguide, comprising a substrate with an upper surface and a lower surface opposite to the upper surface, a central signal line laid on the upper surface of the substrate and two separated ground planes lateral to the central signal line and an underneath ground plane laid on the lower surface of the substrate, wherein a first through hole is created next to the grounded coplanar waveguide and near one end of the central signal line, and the first through hole penetrates through the substrate and the underneath ground plane, and a configuration of the first through hole defines a first geometric center;
• a metallic ring, placed underneath the grounded coplanar waveguide, and having a second through hole;
• and
• a coaxial connector, having a center conductor, a dielectric body and an external conductor, wherein a portion of the external conductor is a mounting wall for the purpose of mechanical assembly, the center conductor comprises a first part and a second part, the first part of the center conductor is surrounded by the dielectric body, which fills the space between the first part of the center conductor and the external conductor, the second part of the center conductor extends out of the mounting wall, passing through the second through hole of the metallic ring first and then the first through hole next to the grounded coplanar waveguide, wherein the position of the center conductor within the first through hole is eccentric with respect to the first geometric center, and at last the center conductor is connected to the central signal line, and an extension direction of the center conductor is perpendicular to a longitudinal direction of the central signal line.