A “core” or “inlay” for a smartcard may comprise a first metal layer and a second metal layer, and may be formed by folding a single metal layer upon itself. A module cavity may be formed in the first metal layer by laser cutting, prior to laminating. An adhesive layer may be disposed between the two metal layers. A module opening may be formed in the second metal layer by milling, after laminating the first metal layer to the second metal layer. A slit in a metal layer may extend from an outer edge of the layer to the cavity or opening, thereby forming a coupling frame. The slit may have a termination hole at either end or at both ends of the slit. The slits of two metal layers may be positioned differently than one another.