Tuned antenna resonant circuit of a passive transponder

• US 6,952,560 B2
• Filed: 05/13/2002
• Issued: 10/04/2005
• Est. Priority Date: 05/18/2001
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Feibig, Cordula, Friedrich, Ulrich
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Jackson, Blane J.
• Application Number:
  US10/145,160
• Publication Number:
  US 20020171602A1
• Time in Patent Office: 1,240 Days
• Field of Search: 340/572.1, 340/10.1, 340/10.5, 340/572.5, 340/572.7, 455/19, 455/215, 455/344, 455/41.1, 455/41.2, 343/895, 343/700.MS
• US Class Current: 455/41.1
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• 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

Abstract

A tuned antenna resonant circuit substantially increases the range of a passive transponder in a high-frequency electromagnetic carrier field, in that the real and imaginary parts of the impedance associated with the contact surface of the antenna contact are minimized and the energy absorbed from the carrier field by a serial resonant circuit is used to the greatest possible extent for generating the supply voltage for the integrated circuit of the transponder.

Claims

1. A tuned antenna resonant circuit of a passive transponder, the operating energy of which is capacitively drawn from a high-frequency electromagnetic carrier field, and

which has a semiconductor body with an integrated circuit (IS) with a signal part (ST) with reference potential connection,

which has an antenna arrangement arranged on a substrate,

the antenna arrangement is linked to the integrated circuit (IS) via a contact surface (BP) connected on the semiconductor body,

in which the antenna arrangement (AN) forms a serial resonant circuit with an input capacitor of the integrated circuit (IS),

wherein parasitic, capacitive and resistive parts, which form a current path between the contact surface (BP) and the reference potential, are reduced in order to raise the quality of the antenna resonant circuit,

wherein the current path is divided into a first current path and a second current path at at least one point by means of a series connection and a parallel connection of the capacitive and resistive parts, and

wherein the parallel connection of a low capacitance of low quality and a low capacitance of high quality is connected in series to a first capacitance of high quality.

2. The tuned antenna resonant circuit according to claim 1, wherein the low capacitances comprise diodes.

3. The tuned antenna resonant circuit according to claim 1, further comprising an insulating layer and a conductive layer (ALB2), which together with the contact surface (BP) forms a capacitor with high quality, and which is implanted in the insulating layer (ISO) lying under the contact surface (BP).

4. The tuned antenna resonant circuit according to claim 1, wherein the low capacitance of low quality and the low capacitance of high quality each respectively have a respective capacitance value of a few femtofarads.

5. A semiconductor arrangement for implementing a tuned antenna resonant circuit of a passive transponder, the operating energy of which is capacitively drawn from a high-frequency electromagnetic carrier field, and which has a semiconductor body with an integrated circuit (IS) with a signal part (ST) with reference potential connection,

which has an antenna arrangement arranged on a substrate,

the antenna arrangement is linked to the integrated circuit (IS) via a contact surface (BP) connected on the semiconductor body,

in which the antenna arrangement (AN) forms a serial resonant circuit with an input capacitor of the integrated circuit (IS),

wherein parasitic, capacitive and resistive parts, which form a current path between the contact surface (BP) and the reference potential, are reduced in order to raise the quality of the antenna resonant circuit,

wherein the semiconductor arrangement includes a first conductive layer (ALB1) as the contact surface (BP) for connecting the antenna arrangement (AN) to the integrated circuit (IS), an insulating layer (ISO), a first zone (D1) of a first conductivity type, a second zone (D2) of a second conductivity type, and a third highly doped zone (D2P) of the second conductivity type, which links a contact (ALK), which has a reference potential, to a semiconductor substrate,

wherein

a second conductive layer (ALB2), the lateral extent of which is greater than the extent of the first conductive layer (ALB1), is arranged within the insulating layer (ISO), and

the second conductive layer (ALB2) has a connection to the first zone (D1) in order to form a Schottky diode, and

the first zone (D1) surrounds the third highly doped zone (D2P).

6. The semiconductor arrangement according to claim 5,

wherein a fourth zone (D2PP) of the second conductivity type, which is surrounded by the first zone (D1), is arranged under a connector area of the second conductive layer (ALB2).

7. A passive transponder arrangement adapted to extract an operating energy therefor from a received high-frequency electromagnetic carrier field, comprising:

a semiconductor body including an integrated circuit with a signal circuit part that includes an input capacitor and is connected to a reference potential connection; and

an antenna arrangement arranged on a substrate and connected to said integrated circuit via a contact surface provided on said semiconductor body;

wherein;

said antenna arrangement and said input capacitor together form a serial resonant circuit;

a current path including capacitances and resistances is formed between said contact surface and said reference potential connection;

said current path includes a first current sub-path and a second current sub-path connected parallel to each other, and a serial path connected in series with said first and second current sub-paths;

said first current sub-path includes a first capacitance among said capacitances and a first resistance among said resistances, said second current sub-path includes a second capacitance among said capacitances and a second resistance among said resistances, and said serial path includes a third capacitance among said capacitances; and

compared to one another, said first capacitance is a low capacitance of high quality, said second capacitance is a low capacitance of low quality, and said third capacitance is a capacitance of high quality.

8. The passive transponder arrangement according to claim 7, wherein said first capacitance and said second capacitance each respectively have a capacitance value of a few femtofarads.

9. The passive transponder arrangement according to claim 7, wherein said first resistance is connected parallel to said first capacitance in said first current sub-path, said second resistance is connected parallel to said second capacitance in said second current sub-path, said first current sub-path further includes a first further resistance among said resistances connected in series with said first resistance and said first capacitance, said second current sub-path further includes a second further resistance among said resistances connected in series with said second resistance and said second capacitance, and said serial path further includes further ones of said resistances respectively connected in parallel and in series with said third capacitance.

10. The passive transponder arrangement according to claim 7, having a first diode structure comprising said first capacitance and a second diode structure comprising said second capacitance.

11. The passive transponder arrangement according to claim 10, wherein said first diode structure is a Schottky diode structure formed by a first junction between a metal structure and a semiconductor region, and said second diode structure is a semiconductor-semiconductor diode structure formed by a second junction between two semiconductor regions.

12. The passive transponder arrangement according to claim 10, wherein said first and second diode structures are each respectively formed by a respective junction between two respective semiconductor regions.

13. The passive transponder arrangement according to claim 7, wherein a first capacitance contribution of said first current sub-path is significantly lower than a second capacitance contribution of said second current sub-path so that said first capacitance contribution dominates said second capacitance contribution and determines an overall capacitance of said current path, and wherein a first resistance contribution of said first current sub-path is significantly lower than a second resistance contribution of said second current sub-path so that said first resistance contribution dominates said second resistance contribution and determines an overall resistance of said current path.

14. The passive transponder arrangement according to claim 13, wherein said overall capacitance and said overall resistance of said current path are negligibly small compared to a capacitance and a resistance of said signal circuit part of said integrated circuit.

15. A semiconductor arrangement for implementing a passive transponder with a tuned antenna resonant circuit, comprising a semiconductor component that includes an integrated circuit with a signal circuit part that is connected to a reference potential connection and a contact surface of said semiconductor component that is adapted to be connected to an antenna arrangement for said passive transponder, wherein said semiconductor component comprise:

an insulating layer;

a first conductive layer arranged on said insulating layer and forming said contact surface;

a second conductive layer arranged in said insulating layer and having a lateral extent greater than said first conductive layer;

a first semiconductor region of a first conductivity type that is arranged under said insulating layer and that is electrically connected to said second conductive layer;

a second semiconductor region of a second conductivity type arranged under said insulating layer;

a highly-doped third semiconductor region of the second conductivity type that is surrounded laterally and from below by said first semiconductor region; and

a reference contact terminal connected to said reference potential connection and to said highly-doped third semiconductor region.

16. The semiconductor arrangement according to claim 15, wherein said first semiconductor region contacts and forms a Schottky diode junction with said second conductive layer.

17. The semiconductor arrangement according to claim 15,

wherein said semiconductor component further comprises a fourth semiconductor region of the second conductivity type, which is surrounded laterally and from below by said first semiconductor region and which is interposed and electrically connected between said first semiconductor region and said second conductive layer.

18. The semiconductor arrangement according to claim 15, wherein a lateral distance between said reference contact terminal and a proximate edge of said second conductive layer is about 1 μ

m.