Smart metal card with radio frequency (RF) transmission capability
Ferrite material utilized in a smart metal card as a shield between a metal layer and an antenna does not occupy a complete layer. Instead, only sufficient ferrite material is utilized to track and conform to the antenna.
1. A smart metal card comprising:
a plastic layer having a top surface;
a metal layer overlying the plastic layer, said metal layer having an inner surface;
a groove formed within the inner surface of said metal layer;
antenna windings disposed within said groove and wound along the top surface of or within said plastic layer; and
a strip of ferrite material lining said groove and disposed between the inner surface of the metal layer and the antenna windings, said strip of ferrite material overlying the antenna windings and limited to a length and a width sufficient to track the underlying antenna windings to form an RF shield between the antenna windings and the metal layer.
2. A card as claimed in claim 1 , wherein the antenna windings are wound in proximity to an outer periphery of the plastic layer.
3. A card as claimed in claim 1 , wherein said strip of ferrite material is disposed on the plastic layer so as to overly the antenna windings; and the plastic layer is attached to the inner surface of the metal layer.
4. A card as claimed in claim 1 , wherein the plastic layer includes a chip module containing a chip for processing data and a chip antenna for coupling to the card antenna.
5. A card as claimed in claim 4 wherein the strip of ferrite material is disposed to also shield the chip antenna to improve RF communication between the chip module and the card antenna.
6. A card as claimed in claim 1 , wherein the length and width of the strip of ferrite material extends in a lateral direction, beyond a vertical projection of the underlying windings to improve the RF shielding between the antenna windings and the metal layer.
7. A card as claimed in claim 1 , including a module having a chip and a chip antenna for communicating with the card antenna; wherein the strip of ferrite material is disposed to shield the card antenna and the chip antenna to provide improved RF shielding between the metal layer and the windings of the card antenna and the chip antenna.
8. A card as claimed in claim 1 , including a module having a chip and a chip antenna for communicating with the card antenna; and wherein the strip of ferrite material is disposed to shield the card antenna and the chip antenna to provide RF shielding between the metal layer and the windings of the card antenna and the chip antenna.
9. A card as claimed in claim 1 , including a chip module providing both contactless and contact capability, and wherein said chip module includes contacts for selectively making direct contact to a card reader.
10. A card as claimed in claim 1 , including a chip module containing a chip for processing data and a chip antenna and wherein said card antenna and said chip antenna are on different levels.
11. A card as claimed in claim 1 , including a chip module containing a chip for processing data and a chip antenna and wherein said card antenna and said chip antenna are on the same plastic layer.
12. The smart metal card of claim 1 , wherein the plastic layer further has a width and a length and the metal layer has a width and a length equal to the width and the length of the plastic layer.
13. The smart metal card of claim 12 , wherein the length and the width of the strip of ferrite material conform to the underlying antenna windings.
14. A smart metal card comprising:
a plastic layer having a top surface;
a metal layer overlying the plastic layer, said metal layer having an inner surface;
a groove formed within the inner surface of said metal layer;
antenna windings disposed within and extending below said groove and wound along the top surface of or within said plastic layer; and
a strip of ferrite material filling said groove and disposed between the inner surface of the metal layer and the antenna windings, said strip of ferrite material overlying the antenna windings and limited to a length and a width sufficient to track the underlying antenna windings to form an RF shield between the antenna windings and the metal layer.
15. The smart metal card of claim 14 , wherein the plastic layer further has a width and a length and the metal layer has a width and a length equal to the width and the length of the plastic layer.
16. The smart metal card of claim 15 , wherein the length and the width of the strip of ferrite material conform to the underlying antenna windings.
17. A smart metal card comprising:
a plastic layer having a top surface;
a metal layer overlying the plastic layer, said metal layer having an inner surface;
a groove formed within the inner surface of said metal layer and having a lateral dimension;
antenna windings having a lateral dimension smaller than the later dimension of the groove, the antenna windings disposed within said groove and wound along the top surface of or within said plastic layer; and
a strip of ferrite material lining said groove and disposed between the inner surface of the metal layer and the antenna windings, said strip of ferrite material overlying the antenna windings and limited to a length and a width sufficient to track the underlying antenna windings to form an RF shield between the antenna windings and the metal layer.
18. The smart metal card of claim 17 , wherein the plastic layer further has a width and a length and the metal layer has a width and a length equal to the width and the length of the plastic layer.
19. The smart metal card of claim 18 , wherein the length and the width of the ferrite material conform to the underlying antenna windings.
20. A smart metal card comprising:
a plastic layer with windings wound around the plastic layer to form a card antenna;
a metal layer overlying the plastic layer, said metal layer having an inner surface; and
a groove formed within the inner surface of said metal layer, said groove filled with a ferrite material disposed over the antenna windings, said strip of ferrite material overlying the antenna windings and limited to a length and a width sufficient to track the underlying antenna windings to form an RF shield between the antenna windings and the metal layer.
21. A smart metal card as claimed in claim 20 , wherein said plastic layer has a top surface facing the metal layer and wherein the windings are located along the top surface of said plastic layer.
22. A smart metal card as claimed in claim 20 , wherein said plastic layer has a top surface facing the metal layer and wherein the windings are located within the plastic layer.
23. The smart metal card of claim 20 , wherein the plastic layer further has a width and a length and the metal layer has a width and a length equal to the width and the length of the plastic layer.
24. The smart metal card of claim 23 , wherein the length and the width of the ferrite material conforms to the underlying antenna windings.
25. A method of forming a metal smart card comprising the steps of:
selecting a plastic layer having top and bottom surfaces, a width and a length;
forming a winding along the top surface of the plastic layer or within said plastic layer to form a card antenna;
selecting a metal layer overlying the plastic layer;
forming a groove within the inner surface of said metal layer; and
disposing ferrite material within said groove between the inner surface of the metal layer and the antenna windings and overlying the antenna windings, limiting the ferrite material to a length and a width sufficient to track the underlying antenna windings to form an RF shield between the antenna windings and the metal layer.
26. The method of claim 25 , wherein the plastic layer has a width and a length and the metal layer has a width and a length equal to the width and the length of the plastic layer.
27. The method of claim 26 , further comprising limiting the length and the width of the ferrite material to conform to the underlying antenna windings.