On a multiple-layered PC board the most critical point for antenna design-in is still the ground clearance (GC) area. As previously mentioned, grounding around the GC area is important for proper impedance matching and frequency control. In a multi-layer board all of the layers around the GC area must be connected together to avoid signal coupling/leaking into gaps between the layers. The DC voltage layers can be left floating as long as the metal of that layer does not overlap with the GC area.