Built-in chip transponder with antenna coil

• US 5,373,303 A
• Filed: 12/18/1992
• Issued: 12/13/1994
• Est. Priority Date: 12/30/1991
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: D'Hont, Loek
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US07/993,333
• Time in Patent Office: 725 Days
• Field of Search: 343/787, 343/788, 343/742, 343/866, 343/867, 343/856, 340/505, 340/572, 340/825.54
• US Class Current: 343/788
• 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 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H01Q 7/06 with core of ferromagnetic material H01Q7/02 takes precedence

Abstract

An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that ape to be transmitted by the transponder. The antenna circuit has at least one magnetic circuit of high μ material, and is formed of ceramic core means, that have been built into a depression in a thick-walled surface intended to receive the chip transponder. This thick-walled surface may be of metal. The ceramic core means comprise at least a ceramic core resonator and half a ceramic core that functions as an antenna with its open side facing outward. In one aspect, the ceramic core resonator and the half ceramic core antenna are coupled by means of one or more secondary coils of the closed ceramic core, which also form the coils of the half ceramic core antenna. In another aspect, the secondary coil forms a resonating circuit with at least one capacitive element in series. In yet another aspect, the ceramic core resonator and the half ceramic core antenna are formed by one and the same half ceramic core, which may be closed in part by a magnetic covering disk. In yet another aspect, the resonator may consist of a half ceramic core which is placed against the back of the half ceramic core antenna.

Claims

1. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponder, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at least a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually coupled, one to the other, and

wherein the resonator consists of a closed ceramic core, and wherein the ceramic core resonator and half ceramic core antenna are coupled by means of at least one secondary coil of the closed ceramic core, which also form the coils of the half ceramic core antenna.

2. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponer, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at leas a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually coupled, one to the other,

wherein the resonator consists of a closed ceramic core, and wherein the ceramic core resonator and half ceramic core antenna are coupled by means of at least one secondary coil of the closed ceramic core, which also form the coils of the half ceramic core antenna, and

wherein further said at least one secondary coil forms a resonating circuit with at least one capacitive element in series.

3. An antenna circuit in accordance with claim 2, wherein the resonant circuit is adjusted, with its frequency on the low side of the frequency band and the resonator on the high side of the frequency band.

4. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponder, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at least a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually coupled, one to the other, and

wherein the ceramic core resonator and the half ceramic core antenna are formed by the same half ceramic core having one or more coils.

5. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponder, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at least a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually, coupled one to the other,

wherein the ceramic core resonator and the half ceramic core antenna are formed by the same half ceramic core having one or more coils, and

wherein further the coils are formed as flat disk-shaped coils.

6. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponder, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at least a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually coupled, one to the other,

wherein the ceramic core resonator and the half ceramic core antenna are formed by the same half ceramic core having one or more coils, and

wherein further said half ceramic core is closed in part by a magnetic covering disk.

7. An antenna circuit to be used in conjunction with a chip transponder such that the antenna circuit serves for both the reception of interrogative signals intended for the transponder as well as for response signals that are to be transmitted by the transponder, comprising;

an antenna circuit, having at least one magnetic circuit of high permeability material, for radiating a magnetic field, comprising,

ceramic core means comprising at least a ceramic core resonator and half a ceramic core antenna, having an open side, which functions as an antenna with its open side facing outward, wherein said resonator and antenna are mutually coupled, one to the other, and

wherein the resonator consists of a half of a ceramic core which is abutting said half ceramic core antenna such that a portion of the magnetic energy from the resonator is transferred to the antenna via magnetic coupling.