Abstract: A multilayer printed circuit board has a plurality of planar layers formed with signal conductor lines and return lines grouped around the conductor lines to form pseudo-coaxial transmission lines. The return lines are grouped symmetrically around each signal line, e.g. two, four, or eight return lines at circumferential positions around each signal line. Ground and power planes may be formed with the multilayer structure for shielding and/or for powering electronic components mounted on the structure. The multilayer techniques can also be used to form a multilayer extender card which minimizes crosstalk and is reduced in cost and assembly time as compared to conventional extender boards.