Apparatus and method for improving AC coupling on circuit boards

The invention relates to an apparatus and method for improving AC coupling between adjacent signal traces and between plane splits and signals spanning plane splits on circuit boards. A circuit board includes adjacent conductive means and an oxide means interposed there between. The oxide means is a copper oxide, e.g., cupric or cuprous oxide. In one embodiment, the adjacent conductive means are adjacent voltage reference planes with a split interposed between the conductive means. The copper oxide fills the split. In another embodiment, the adjacent conductive means are differential signal traces. The copper oxide fills a gap between the differential signal traces. The copper oxide is a non-conductive material with an increased dielectric constant as compared to other common dielectric materials used as fillers. The increased dielectric constant increases capacitance, in turn, increasing AC coupling.