Resonant circuit tuning system using magnetic field coupled reactive elements

• US 20070296548A1
• Filed: 06/27/2006
• Published: 12/27/2007
• Est. Priority Date: 06/27/2006
• Status: Abandoned Application

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Inventors: Hall, Stewart E., Herring, Richard, Patterson, Hap
• Application Number:
  US11/475,477
• Publication Number:
  US 20070296548A1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: H03J 1/0008 using a central processing unit, e.g. a microprocessor digital tuning in general H03J5/0245

Abstract

A resonant circuit tuning system and a method for tuning are provided. The resonant circuit tuning system may include an LCR circuit and a reactive element magnetically coupled to the LCR circuit.

Claims

1. A resonant circuit tuning system comprising:

an LCR circuit; and

a reactive element magnetically coupled to the LCR circuit.

2. A resonant circuit tuning system in accordance with claim 1 wherein the reactive element comprises at least one of an inductive element and a capacitive element.

3. A resonant circuit tuning system in accordance with claim 1 wherein the reactive element comprises at least one of a variable inductive element and a variable capacitive element.

4. A resonant circuit tuning system in accordance with claim 1 further comprising a resistive element magnetically coupled to the LCR circuit.

5. A resonant circuit tuning system in accordance with claim 4 wherein the resistive element comprises a variable resistive element.

6. A resonant circuit tuning system in accordance with claim 1 wherein the LCR circuit is configured in at least one of a series and a parallel arrangement.

7. A resonant circuit tuning system in accordance with claim 1 further comprising at least one magnetically coupled winding coupling the reactive element to the LCR circuit.

8. A resonant circuit tuning system in accordance with claim 1 further comprising at least one of a transmitter and receiver connected to the LCR circuit.

9. A resonant circuit tuning system in accordance with claim 1 wherein the LCR circuit comprises an antenna configured to provide at least one of transmission and reception.

10. A resonant circuit tuning system in accordance with claim 1 further comprising a controller connected to the reactive element and configured to control the operation of the reactive element.

11. A resonant circuit tuning system in accordance with claim 8 further comprising a switch connected to the controller to control switching of the reactive element.

12. A resonant circuit tuning system in accordance with claim 10 further comprising a plurality of reactive elements.

13. A resonant circuit tuning system in accordance with claim 10 further comprising a plurality of resistive elements

14. A resonant circuit tuning system in accordance with claim 1 further comprising a plurality of taps connecting the reactive element to at least one coil of the LCR circuit.

15. A resonant circuit tuning system in accordance with claim 1 further comprising a plurality of taps connecting the reactive element to at least one coil of the LCR circuit, the plurality of taps connected to an inductor winding of the LCR circuit.

16. A resonant circuit tuning system in accordance with claim 1 wherein the reactive element is magnetically coupled to an inductive winding of the LCR circuit.

17. A resonant circuit tuning system in accordance with claim 1 further comprising a resistive element magnetically coupled to the LCR circuit and a controller configured to control at least one of a resonant frequency and a Q value of the LCR circuit using the reactive element and the resistive element.

18. A resonant circuit tuning system in accordance with claim 1 wherein the LCR circuit is configured to operate in connection with an Electronic Article Surveillance (EAS) system.

19. An electronic article surveillance (EAS) system comprising:

at least one of a transmitter and a receiver;

at least one antenna connected to the at least one transmitter and receiver; and

a tuning circuit configured to tune the at least one antenna, the tuning circuit comprising at least one reactive element magnetically coupled to the antenna.

20. An EAS system in accordance with claim 19 further comprising a controller configured to control at least one of (i) switching the reactive element and (ii) varying a level of the reactive element.

21. An EAS system in accordance with claim 19 wherein the tuning circuit further comprises at least one resistive element magnetically coupled to the antenna.

22. An EAS system in accordance with claim 21 further comprising a controller configured to control at least one of (i) switching the resistive element and (ii) varying a level of the resistive element.

23. A method for tuning an LCR circuit, the method comprising:

magnetically coupling a reactive element to an inductor of the LCR circuit; and

controlling a resonant frequency of the LCR circuit using the reactive element.

24. A method in accordance with claim 23 wherein the magnetically coupling comprises tapping the reactive element to coils of the inductor of the LCR circuit.

25. A method in accordance with claim 23 wherein the LCR circuit further comprises an antenna.

26. A method in accordance with claim 23 further comprising magnetically coupling a resistive element to an inductor of the LCR circuit and controlling a Q value of the LCR circuit using the resistive element.