Multiple-layer signal conductor
A multiple-layer signal conductor has increased surface area for mitigation of skin effect. Parallel extending elongated strips of conductive material are placed in parallel layers and are separated by a thin layer of dielectric. The elongated strips are conductively connected to one another by regularly spaced vias such that a single signal conductor with multiple conductive layers is formed. During high-speed signaling, the skin effect causes current to concentrate near the surfaces of conductors. The multiple-layer signal conductor, however, has increased surface area with respect to its total cross-sectional area. The effective cross-sectional area which is conductive during high-speed signaling is therefore increased, leading to positive effects on transmission line resistance, heating, signal integrity and signal propagation delay. The multiple-layer signal conductor sees special use on silicon circuit boards and can conduct signals at ten gigahertz or greater for distances of up to five inches without rebuffering or termination.
Conn, RO. (2011). IPC No. U.S. Multiple-layer signal conductor. (Patent No. 7978029).