Transponder and antenna

• US 6,930,646 B2
• Filed: 08/22/1996
• Issued: 08/16/2005
• Est. Priority Date: 08/22/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Materials Corporation
• Original Assignee: Mitsubishi Materials Corporation
• Inventors: Tsuchida, Takashi, Endo, Takanori, Yahata, Seiro, Miyaki, Masami
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US08/701,457
• Publication Number:
  US 20030107523A1
• Time in Patent Office: 3,281 Days
• Field of Search: H01/Q00.7/00, 343/718, 343/788, 343/742, 343/867, 235/491, 340/572, 340/572.6, 340/572.7
• US Class Current: 343/718
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07781 the coil being fabricated in a winding process
• CPC Class Codes: H01F 1/37 in a bonding agent
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 7/06 with core of ferromagnetic material H01Q7/02 takes precedence

Abstract

An antenna for a transponder comprises a magnetic core composed of layered amorphous metallic thin plates or composite plates of soft magnetic flakes and a synthetic resin, and a coil wound on the magnetic core. A transponder comprises two antennas set forth above, and a spiral antenna.

Claims

1. An antenna for a transponder comprising a three-dimensional magnetic core composed of a single stack of rectangular metallic thin plates, and a coil having windings wound on said magnetic core such that said windings are arranged parallel to a greatest rectangular dimension of said plates forming said magnetic core.

2. An antenna for a transponder according to claim 1, wherein corners of said thin plates are rounded.

3. An antenna for a transponder according to claim 1, wherein said thin plates comprise an amorphous magnetic material.

4. An antenna for a transponder according to claim 1, wherein the thickness of each one of said thin plates is 20 to 50 μ

m.

5. An antenna for a transponder according to claim 1, wherein said magnetic core comprises three to sixteen of said thin plates.

6. An antenna for a transponder according to claim 1, wherein said thin plates are insulated from one another by oxidizing each of their surfaces.

7. An antenna for a transponder according to claim 1, wherein the diameter of a conductor comprising said coil is 100 to 200 μ

m.

8. An antenna for a transponder according to claim 1, wherein the thickness of the antenna is 0.4 mm or less.

9. An antenna for a transponder according to claim 1, wherein said antenna for a transponder is a size suitable for use as at least one of an ID card, a commuter pass and a coupon ticket which operates at a frequency of 40 to 200 kHz.

10. The antenna for a transponder according to claim 1, wherein each corner of said thin plates is reduced to form an oblique angle.

11. An antenna for a transponder comprising a three-dimensional rectangular plate magnetic core comprising a single stack of rectangular metallic thin plates, each plate composed of a composite material of soft magnetic flakes and a synthetic resin, and a coil having windings wound on said magnetic core such that said windings are arranged perpendicular to a greatest rectangular dimension of the magnetic core.

12. An antenna for a transponder according to claim 11, wherein the soft magnetic material composing each one of said flakes is selected from the group consisting of pure iron, silicon steel, a permalloy and an iron/cobalt amorphous alloy.

13. An antenna for a transponder according to claim 12, wherein the soft magnetic material composing each one of said flakes is a cobalt amorphous alloy.

14. An antenna for a transponder according to claim 11, wherein each one of said flakes has a thickness of 30 μ

m or less and a diameter of 50 to 2,000 μ

m.

15. An antenna for a transponder according to claim 11, wherein each one of said flakes has a thickness of 10 μ

m or less and a diameter of 100 to 1,000 μ

m.

16. An antenna for a transponder according to claim 11, wherein said synthetic resin is selected from the group consisting of thermoset resins, including epoxy resins, phenol resins, urea resins, unsaturated polyester resins, diacrylphthalate resins, melamine resins, silicone resins, and polyurethane resins;

and thermoplastic resins, including polyethylene resins, polypropylene resins, vinyl chloride resins, fluoroplastics, methacrylate resins, polystyrene resins, AS resins, ABS resins, ABA resins, polycarbonate resins, polyacetal resins, and polyimide resins.

17. An antenna for a transponder according to claim 11, wherein the amount of said synthetic resin in the composite material is 3 to 50% by weight.

18. An antenna for a transponder according to claim 11, wherein said flake comprises a cobalt base amorphous alloy, said synthetic resin is an epoxy resin, and the amount of said synthetic resin in the composite material is 10 to 40% by weight.

19. An antenna for a transponder according to claim 11, wherein said magnetic core has a thickness of 0.3 mm to 1 mm, a width of 10 to 25 mm and a length of 60 to 80 mm.

20. An antenna for a transponder according to claim 11, wherein said magnetic core has a thickness of 0.3 to 1 mm, a width of 10 to 25 mm and a length of 60 to 80 mm.

21. An antenna for a transponder according to claim 11, wherein the diameter of a conductor comprising said coil is 100 to 200 μ

m.

22. An antenna for a transponder according to claim 11, wherein said antenna for a transponder is a size suitable for use as at least one of an ID card, a commuter pass and a coupon ticket which operates at a frequency over 100 kHz.

23. An transponder comprising two plate antennas set forth in claim 11, and an air-core antenna composed of a spirally wound conductor,

wherein said three antennas have respective axes which are mutually perpendicular to one another.

24. A transponder according to claim 23, wherein the axes of said two or three antennas are perpendicular to each other.

25. A transponder according to claim 23, wherein said two plate antennas are provided in the plate transponder so that the axes of said two coils are perpendicular to each other, and said air-core antenna composed of the spirally wound conductor is provided in the plate transponder so that the axis thereof is perpendicular to the transponder plate.

26. A transponder according to claim 23, wherein said antenna for a transponder is a size suitable for use as at least one of an ID card, a commuter pass and a coupon ticket which operates at a frequency over 100 kHz.