Patent ID: 7705695

Claim:
A composite via structure in a multilayer printed circuit board (PCB) comprising: a first functional part extending in a vertical direction from a first pad disposed at one side of the PCB to a special pad embedded in the PCB for a connection to a planar transmission line, providing a low-return loss and shielded vertical transition between the first pad and the special pad, and including: a signal via conductor as a through-plated hole in the PCB with the first pad and special pad being connected to the signal via conductor; an assembly of ground vias surrounding the signal via conductor and forming said vertical transition of a predetermined characteristic impedance; a clearance hole separating the signal via conductor, first and special pads from grounding conductors of the composite via structure and having predetermined dimensions and shape providing the low return loss of said vertical transition; a second functional part providing an open-circuited resonant length extending in the vertical direction from said special pad to the second pad disposed on the opposite side of the PCB, and including: the same signal via conductor as the first functional part; and the same assembly of ground vias surrounding the signal via conductor as the first functional part; and a plurality of conductive plates disposed at the conductor layers of the PCB, connected to the signal via conductor, and separated from grounding conductors by isolating slots, wherein said second pad is connected to the signal via conductor and separated from grounding conductors disposed at the same conductor layer by an isolating slot.