Abstract: An electromagnetically-decoupled stripline circuit on a conventional circuitboard includes a center groundplane and two coplanar striplines that are sandwiched within a dielectric material between two outer groundplanes. A plurality of connectors conductively interconnect the groundplanes. The center groundplane has a decoupling strip portion lying between the striplines that is split in two by a gap. The gap traverses the direction an electromagnetic field would propagate from one of the striplines toward the other, and a pair of the connectors are positioned to straddle the gap. Z-wires, plated-through holes, and additional gaps may be employed.