The present invention is a reconfigurable substrate which includes at least one signal line layer stack. Each signal line layer stack is defined to include two substantially parallel insulating layers and a signal line layer interposed between the two insulating layers and substantially parallel to the insulating layers. The substrate includes at least one conductive isolation layer adjacent to at least one signal line layer stack and substantially parallel to the at least one signal line layer stack. The substrate is reconfigurable to different performance levels by adding or removing at least one conductive isolation layer.