TUNING A NFC ANTENNA OF A DEVICE

• US 20180295489A1
• Filed: 03/30/2018
• Published: 10/11/2018
• Est. Priority Date: 05/23/2015
• Status: Active Grant

• Current Assignee: Block, Inc. (f/k/a Square, Inc.)
• Original Assignee: Block, Inc. (f/k/a Square, Inc.)
• Inventors: Lamba, Kartik, Wade, Jeremy, Maibach, Matthew H., Dorogusker, Jesse
• Granted Patent: US 10,667,106 B2
• Time in Patent Office: Days
• CPC Class Codes: G06K 7/10148 the step consisting of dynamically tuning the resonant circuit of the interrogation device that is emitting the interrogation signal, e.g. for impedance matching inside of the interrogation device for tuning related to loop aerials in general H01Q7/00
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06Q 20/3278 RFID or NFC payments by means of M-devices
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04B 1/401 for selecting or indicating operating mode
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A NFC object reader'"'"'s NFC antenna system configured to dynamically change an element of the NFC antenna system to maintain the NFC antenna system'"'"'s antenna default resonant frequency. The NFC antenna system can be configured to include a tuning subsystem, integrated with sensors to trigger tuning of NFC antenna system'"'"'s antenna.

Claims

1. A near field communication (NFC) payment object reader comprising:

a power subsystem including a power source;

an NFC subsystem including an antenna; and

a tuning subsystem that tunes the antenna, the tuning subsystem receiving information from the power subsystem, wherein based on the information from the power subsystem, the tuning subsystem initiates;

a first tuning process while the information from the power subsystem indicates that a power level of the power source is below a predetermined power level threshold; and

a second tuning process while the information from the power subsystem indicates that the power level of the power source exceeds the predetermined power level threshold.

2. The NFC payment object reader of claim 1, wherein the power source supplies a first amount of power to the antenna under the first tuning process, wherein the power source supplies a second amount of power to the antenna under the second tuning process, and wherein the first amount of power is decreased in comparison to the second amount of power.

3. The NFC payment object reader of claim 1, wherein the NFC subsystem generates a first field with a first field strength using the antenna under the first tuning process, wherein the NFC subsystem generates a second field with a second field strength using the antenna under the second tuning process, and wherein the first field strength is reduced in comparison to the second field strength.

4. The NFC payment object reader of claim 1, wherein the first tuning process pauses tuning of the NFC antenna.

5. A near field communication (NFC) payment object reader comprising:

a power source;

an NFC subsystem that includes an antenna; and

a tuning subsystem that tunes the antenna, wherein the tuning subsystem tunes the antenna using a first tuning process while a power level of the power source is below a predetermined power level threshold, wherein the tuning subsystem tunes the antenna using a second tuning process while the power level of the power source exceeds the predetermined power level threshold.

6. The NFC payment object reader of claim 5, wherein the power source supplies a first amount of power to the antenna under the first tuning process, wherein the power source supplies a second amount of power to the antenna under the second tuning process, and wherein the first amount of power is decreased in comparison to the second amount of power.

7. The NFC payment object reader of claim 5, wherein the NFC subsystem generates a first field with a first field strength using the antenna under the first tuning process, wherein the NFC subsystem generates a second field with a second field strength using the antenna under the second tuning process, and wherein the first field strength is reduced in comparison to the second field strength.

8. The NFC payment object reader of claim 5, wherein the tuning subsystem uses the first tuning process after using the second tuning process in response to a reduction in the power level of the power source.

9. The NFC payment object reader of claim 5, wherein the tuning subsystem uses the second tuning process after using the first tuning process in response to an increase in the power level of the power source.

10. The NFC payment object reader of claim 5, further comprising:

an electrical contact that receives power from an external source; and

a battery charger that uses the power received via the electrical contact to charge a rechargeable battery, wherein the power source includes at least the rechargeable battery.

11. The NFC payment object reader of claim 5, wherein the first tuning process is associated with a first tolerance for deviation from a desired frequency of the NFC subsystem, wherein the second tuning process is associated with a second tolerance for deviation from the desired frequency of the NFC subsystem, and wherein the first tolerance for deviation from the desired frequency of the NFC subsystem is greater than the second tolerance for deviation from the desired frequency.

12. The NFC payment object reader of claim 5, wherein the tuning subsystem tunes the antenna more frequently while using the second tuning process than while using the first tuning process.

13. The NFC payment object reader of claim 5, wherein the tuning subsystem includes one or more variable capacitors that the tuning subsystem uses to tune a strength of a field generated using the antenna.

14. A method of tuning a near field communication (NFC) payment object reader, the method comprising:

identifying a power level of a power source of the NFC payment object reader;

identifying that the power level of the power source exceeds a predetermined power level threshold;

tuning an NFC antenna of the NFC payment object reader according to a first tuning process while the power level of the power source exceeds the predetermined power level threshold;

identifying that the power level of the power source is below the predetermined power level threshold; and

tuning the NFC antenna of the NFC payment object reader according to a second tuning process while the power level of the power source is below the predetermined power level threshold.

15. The method of claim 14, further comprising:

supplying a first amount of power from the power source of the NFC payment object reader to the NFC antenna while the NFC antenna is tuned according to the first tuning process; and

supplying a second amount of power from the power source of the NFC payment object reader to the NFC antenna while the NFC antenna is tuned according to the second tuning process, wherein the first amount of power is decreased in comparison to the second amount of power.

16. The method of claim 14, further comprising:

generating a first field with a first field strength using the NFC antenna while the NFC antenna is tuned according to the first tuning process; and

generating a second field with a second field strength using the NFC antenna while the NFC antenna is tuned according to the second tuning process, wherein the first field strength is reduced in comparison to the second field strength.

17. The method of claim 16, further comprising:

adjusting an amount of capacitance in a tuning circuit, thereby causing the NFC antenna to switch between generating the second field with the second field strength and generating the first field with the first field strength.

18. The method of claim 17, wherein adjusting the amount of capacitance in the tuning circuit includes switching one or more field effect transistor (FET) switches to adjust a number of capacitors electrically connected to the tuning circuit.

19. The method of claim 14, wherein identifying that the power level of the power source is below the predetermined power level threshold occurs after identifying that the power level of the power source meets or exceeds the predetermined power level threshold, and wherein tuning the NFC antenna of the NFC payment object reader according to the second tuning process occurs after tuning the NFC antenna of the NFC payment object reader according to the first tuning process.

20. The method of claim 14, wherein identifying that the power level of the power source meets or exceeds the predetermined power level threshold occurs after identifying that the power level of the power source is below the predetermined power level threshold, and wherein tuning the NFC antenna of the NFC payment object reader according to the first tuning process occurs after tuning the NFC antenna of the NFC payment object reader according to the second tuning process.