US Patent 8366009 Coupling in and to RFID smart cards

A dual interface (DI) smart card (100) comprising a chip module (CM), a module antenna (MA), a card body (CB) and a card antenna (CA) having two windings (D,E) connected with reverse phase as a “quasi-dipole”. Capacitive stubs (B,C) connected with an antenna structure (A) of the module antenna (MA). The module antenna (MA) overlaps only one of the windings (D or E) of the card antenna (CA). The card antenna (CA) may be formed from one continuous wire. Ferrite (156) shielding the module antenna (MA) from contact pads (CP) and for enhancing coupling between the module antenna (MA) and the card antenna (CA).