Inductive reader device and method with integrated antenna and signal coupler

• US 6,584,301 B1
• Filed: 05/25/2000
• Issued: 06/24/2003
• Est. Priority Date: 05/25/2000
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bohn, Thomas B., Rachwalski, Richard S., Schamberger, Mark A.
• Primary Examiner(s): NGUYEN, DUC M
• Application Number:
  US09/578,433
• Time in Patent Office: 1,125 Days
• Field of Search: 455/41, 455/73, 455/106, 455/101, 235/375-386, 342/42-51, 340/825.25, 340/825.54, 340/825.31, 340/825.33, 340/870.28, 340/870.31, 340/870.33, 340/10.1, 340/10.2, 340/10.3
• US Class Current: 455/41.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/48 Transceivers

Abstract

An inductive reader device (104) communicates with a transponder (102) using electromagnetic coupling. The reader device includes a transmitter (112), a receiver (114), a first coil element (116), and a second coil element (118). The first coil element is directly connected to the transmitter to emit a radio frequency excitation signal. The first coil element receives a radio frequency response signal from the transponder via electromagnetic coupling. The second coil element is directly connected to the receiver to provide a response signal to the receiver. The second coil element is loosely or inductively coupled to the first coil element via a predetermined mutual inductance due to the spatial relationship between the first coil element and the second coil element. Hence, the second coil element receives the radio frequency response signal from the first coil element. Advantageously, a signal coupler required for the receiver is integrated with an antenna element by virtue of the second coil element.

Claims

1. An inductive reader device comprising:

a transmitter;

a receiver;

a first coil element connected to the transmitter, wherein the first coil element emits and receives radio frequency signals via inductive coupling to a transponder, the radio frequency signals including a data signal from the transponder; and

a second coil element connected to the receiver and inductively coupled to the first coil element such that the receiver receives from the second coil element via the first coil element the data signal from the transponder.

2. The device of claim 1 wherein the second coil element is spaced in relation to the first coil element to provide a predetermined mutual inductive coupling between the first coil element and the second coil element.

3. The device of claim 2 wherein the first coil element is substantially larger than the second coil element.

4. The device of claim 1 wherein the first coil element and the second coil element are both traces on a printed circuit board.

5. The device of claim 4 wherein the first coil element forms a generally rectangular configuration and the second coil element forms a generally rectangular configuration.

6. The device of claim 5 wherein the second coil element is placed near a corner of the generally rectangular configuration of the first coil element.

7. The device of claim 4 wherein the first coil element forms a generally circular configuration and the second coil element forms a generally circular configuration.

8. The device of claim 1 wherein the first coil element and the second coil element are both coils of wire.

9. The device of claim 1 wherein the first coil element and the second coil element are both coils of wire affixed in a non-conductive material.

10. The device of claim 1 wherein the first coil element is at least one of a printed circuit board trace, conductive ink, and a wire and wherein the second coil element is at least one of a printed circuit board trace, conductive ink, and a wire.

11. A radio frequency communications system comprising:

a transponder; and

a reader device, the reader device comprising;

a transmitter;

a receiver;

a first coil element connected to the transmitter;

wherein the first coil element emits and receives radio frequency signals via inductive coupling to the transponder, the radio frequency signals including a data signal from the transponder; and

a second coil element connected to the receiver and inductively coupled to the first coil element such that the receiver receives from the second coil element via the first coil element the data signal from the transponder.

12. The system of claim 11 wherein the second coil element is spaced in relation to the first coil element to provide a predetermined mutual inductive coupling between the first coil element and the second coil element.

13. The system of claim 12 wherein the first coil element is substantially larger than the second coil element.

14. The system of claim 11 wherein the first coil element and the second coil element are both traces on a printed circuit board.

15. The system of claim 14 wherein the first coil element forms a generally rectangular configuration and the second coil element forms a generally rectangular configuration.

16. The system of claim 15 wherein the second coil element is placed near a corner of the generally rectangular configuration of the first coil element.

17. The system of claim 11 wherein the first coil element is at least one of wire, a trace on a printed circuit board, and conductive ink and wherein the second coil element is at least one of wire, a trace on a printed circuit board, and conductive ink.

18. The system of claim 11 wherein the transponder comprises:

a coil that receives radio frequency signals;

a transceiver connected to the coil to receive radio frequency signals from the coil; and

a control circuit coupled to the transceiver to control the data signal from the transponder.

19. An inductive reader device comprising:

a transmitter;

a receiver;

a first coil element connected to the transmitter;

wherein the first coil element emits and receives radio frequency signals via inductive coupling to a transponder, the radio frequency signals including a data signal from the transponder; and

a second coil element connected to the receiver and inductively coupled to the first coil element such that the second coil element receives a coupled signal from the first coil element and the receiver receives the coupled signal from the second coil element, the coupled signal including the data signal from the transponder.

20. The device of claim 19 wherein the second coil element is spaced in relation to the first coil element to provide a predetermined mutual inductive coupling between the first coil element and the second coil element.

21. The device of claim 20 wherein the first coil element is substantially larger than the second coil element.

22. The device of claim 19 wherein the first coil element and the second coil element are both traces on a printed circuit board.

23. The device of claim 22 wherein the first coil element forms a generally rectangular configuration and the second coil element forms a generally rectangular configuration.

24. The device of claim 23 wherein the second coil element is placed near a corner of the generally rectangular configuration of the first coil element.

25. The device of claim 22 wherein the first coil element forms a generally circular configuration and the second coil element forms a generally circular configuration.

26. The device of claim 19 wherein the first coil element and the second coil element are both coils of wire.

27. The device of claim 19 wherein the first coil element and the second coil element are both coils of wire affixed in a non-conductive material.

28. The device of claim 19 wherein the first coil element is at least one of wire, a trace on a printed circuit board, and conductive ink and wherein the second coil element is at least one of a printed circuit board trace, conductive ink, and a wire.

29. A method for communicating between an inductive reader device and a transponder, the method comprising the steps of:

A) coupling a first coil element connected to a transmitter of the inductive reader device with the transponder via inductive coupling;

B) receiving a radio frequency signal produced by the transponder in response to inductive coupling between the transponder and the first coil element, the radio frequency signal including a data signal; and

C) inductively coupling a second coil element connected to a receiver of the inductive reader device with the first coil element such that the second coil element receives a coupled signal from the first coil element and the receiver receives the coupled signal from the second coil element, the coupled signal including the data signal from the transponder.

30. The method of claim 29 wherein the second coil element is spaced in relation to the first coil element to provide a predetermined mutual inductive coupling between the first coil element and the second coil element.

31. The method of claim 30 wherein the first coil element is substantially larger than the second coil element.

32. The method of claim 29 wherein the first coil element and the second coil element are both traces on a printed circuit board.

33. The method of claim 32 wherein the first coil element forms a generally rectangular configuration and the second coil element forms a generally rectangular configuration.

34. The method of claim 33 wherein the second coil element is placed near a corner of the generally rectangular configuration of the first coil element.

35. The method of claim 32 wherein the first coil element forms a generally circular configuration and the second coil element forms a generally circular configuration.

36. The method of claim 29 wherein the first coil element and the second coil element are both coils of wire.

37. The method of claim 29 wherein the first coil element and the second coil element are both coils of wire affixed in a non-conductive material.

38. The method of claim 29 wherein the first coil element is at least one of wire, a trace on a printed circuit board, and conductive ink and wherein the second coil element is at least one of a printed circuit board trace, conductive ink, and a wire.

39. The method of claim 29 wherein step A further comprises:

A1) the inductive reader device emitting an excitation signal; and

A2) the excitation signal energizing the transponder to produce the radio frequency signal.