Method of and system for tuning an antenna

• US 8,391,817 B2
• Filed: 05/19/2009
• Issued: 03/05/2013
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Noel, Denis
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US13/001,568
• Publication Number:
  US 20110111706A1
• Time in Patent Office: 1,386 Days
• Field of Search: 4551931-1933, 455/226.2
• US Class Current: 455/193.1
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00

Abstract

A method of tuning an antenna is provided, wherein the method comprises receiving a first signal strength indicator indicating a signal strength of a first data signal transmitted by an antenna on a first frequency, receiving a second signal strength indicator indicating a signal strength of a second data signal transmitted by the antenna on a second frequency different to the first frequency, determining a tuning control signal based on the first signal strength indicator and the second signal strength indicator, and tuning the antenna based on the control signal.

Claims

1. A method of tuning an antenna, the method comprising:

receiving a first signal strength indicator indicating a signal strength of a first data signal transmitted by an antenna on a first frequency,

receiving a second signal strength indicator indicating a signal strength of a second data signal transmitted by the antenna on a second frequency different from the first frequency,

determining a tuning control signal based on the first signal strength indicator and the second signal strength indicator, wherein the tuning control signal is based on a difference between the first signal strength indicator and the second signal strength indicator, wherein the difference between the first signal strength indicator and the second signal strength indicator is found by subtracting the first signal strength indicator from the second signal strength indicator, and

tuning the antenna based on the tuning control signal.

2. The method according to claim 1, further comprising:

measuring the first signal strength indicator, and

measuring the second signal strength indicator.

3. The method according to claim 2, further comprising:

amplifying at least one of the first and the second data signals before measuring the signal strength indicator.

4. The method according to claim 2,

wherein at least one of the first and the second data signals comprises a plurality of symbols having a predetermined timing, and

wherein the measuring of at least one of the first signal strength indicator and the second signal strength indicator is synchronized with the predetermined timing.

5. The method according to claim 1,

wherein the signal strength indicator relates to an amplitude of the data signal.

6. The method according to claim 1,

wherein the signal strength indicator relates to a current consumption of a device which includes the antenna.

7. The method according to claim 1,

wherein the tuning is performed by tuning a capacity of the antenna.

8. The method according to claim 1,

wherein at least one of the first signal strength indicator and the second signal strength indicator relates to more than one data signal.

9. The method according to claim 1, further comprising:

receiving a third signal strength indicator indicating a signal strength of a third data signal transmitted by the antenna on a third frequency different from the first frequency and the second frequency,

wherein the control signal is determined based on the first, the second and the third signal strength indicators.

10. The method according to claim 1,

wherein for transmission of data signals a protocol is used which is based on a slotted access, and

wherein at least one of the first data signal and the second data signal is transmitted during a predetermined time slot.

11. The method according to claim 10,

wherein the predetermined time slot is an RCH slot.

12. The method according to claim 10,

wherein at least one of the first data signal and the second data signal is a specific tune signal.

13. A non-transitory program element, which, when executed by a processor, implements a method according to claim 1.

14. A computer-readable medium, in which a computer program is stored which, when being executed by a processor, is adapted to control or carry out a method according to claim 1.

15. The method according to claim 1,

wherein a negative difference between the first signal strength indicator and the second signal strength indicator indicates a resonant frequency of the antenna is too high and a positive difference between the first signal strength indicator and the second signal strength indicator indicates that the resonant frequency is too low.

16. The method according to claim 1,

wherein in case the difference between the first signal strength indicator and the second signal strength indicator is negative, capacity of the antenna is decreased, and in case the difference between the first signal strength indicator and the second signal strength indicator is positive, capacity of the antenna is increased.

17. A system for tuning an antenna, the system comprising:

a transducer having;

a receiving terminal, adapted to receive a first signal strength indicator indicating a signal strength of a first data signal transmitted by an antenna on a first frequency, and further adapted to receive a second signal strength indicator indicating a signal strength of a second data signal transmitted by the antenna on a second frequency different from the first frequency,

a determining unit adapted to determine a tuning control signal based on a difference between the first signal strength indicator and the second signal strength indicator, wherein the difference between the first signal strength indicator and the second signal strength indicator is found by subtracting the first signal strength indicator from the second signal strength indicator, and

a tuning unit adapted to tune the antenna based on the tuning control signal.

18. The system according to claim 17,

wherein a negative difference between the first signal strength indicator and the second signal strength indicator indicates a resonant frequency of the antenna is too high and a positive difference between the first signal strength indicator and the second signal strength indicator indicates that the resonant frequency is too low.

19. The system according to claim 17,

wherein in case the difference between the first signal strength indicator and the second signal strength indicator is negative, capacity of the antenna is decreased, and in case the difference between the first signal strength indicator and the second signal strength indicator is positive, capacity of the antenna is increased.