Methods for tuning an adaptive impedance matching network with a look-up table

• US 8,421,548 B2
• Filed: 11/16/2011
• Issued: 04/16/2013
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Research in Motion RF Inc (Blackberry Limited)
• Inventors: Spears, John H., Smith, Wayne E., Sui, Chenggang, Zhu, Yongfei
• Primary Examiner(s): JONES, STEPHEN E
• Application Number:
  US13/297,951
• Publication Number:
  US 20120056689A1
• Time in Patent Office: 517 Days
• Field of Search: 333/17.3, 333/32, 333/33
• US Class Current: 333/17.3
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H03H 11/30 Automatic matching of source impedance to load impedance
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H

Abstract

Methods for generating a look-up table relating a plurality of complex reflection coefficients to a plurality of matched states for a tunable matching network. Typical steps include measuring a plurality of complex reflection coefficients resulting from a plurality of impedance loads while the tunable matching network is in a predetermined state, determining a plurality of matched states for the plurality of impedance loads, with a matched state determined for each of the plurality of impedance loads and providing the determined matched states as a look-up table. A further step is interpolating the measured complex reflection coefficients and the determined matching states into a set of complex reflection coefficients with predetermined step sizes.

Claims

1. An apparatus comprising a controller which when executing computer instructions is operable to adaptively tune a tunable impedance matching network with a lookup table, the lookup table containing sets of parameters corresponding to matched states for the tunable impedance matching network, said controller being operable for:

selecting a parameter from the group consisting of complex reflection coefficients, current drain, incident power, reflected power, control setting of the tunable matching network, temperature, input power level, reliability considerations and linearity considerations;

determining the closest match to the selected parameter in the lookup table;

using the closest match to the selected parameter in the lookup table to tune the tunable impedance matching network, wherein the tunable impedance matching network includes voltage, variable capacitors, wherein the voltage variable capacitors are ferroelectric capacitors; and

controlling the ferroelectric capacitors with digital-to-analog converters.

2. The apparatus of claim 1, wherein the controller is operable for:

selecting the parameter to minimize tolerance variations based upon temperature coefficient, component tolerance or tolerance over time.

3. The apparatus of claim 1, wherein the ferroelectric capacitors are first and second ferroelectric capacitors that are connected with first and second digital-to-analog converters of the digital-to-analog converters, respectively.

4. The apparatus of claim 1, wherein the tunable impedance matching network includes a rectifier, and an analog-to-digital converter, wherein the rectifier provides a rectified value of a forward RF power to the analog-to-digital converter, and wherein the analog-to-digital converter provides a digital signal representing the rectified value to the processor.

5. The apparatus of claim 1, wherein the tunable impedance matching network includes a rectifier, and an analog-to-digital converter, wherein the rectifier provides a rectified value of a reverse RF power to the analog-to-digital converter, and wherein the analog-to-digital converter provides a digital signal representing the rectified value to the processor.

6. A communication device comprising:

a memory to store a lookup table and computer instructions, wherein the lookup table includes sets of parameters corresponding to matched states for the tunable impedance matching network;

a tunable impedance matching network comprising a ferroelectric capacitor;

a digital-to-analog converter; and

a controller coupled with the memory, the tunable impedance matching network and the analog-to-digital converter, wherein the controller, responsive to executing the computer instructions, performs operations comprising;

selecting a parameter from the group consisting of complex reflection coefficients, current drain, incident power, reflected power, control setting of the tunable matching network, temperature, input power level, reliability considerations and linearity considerations;

determining the closest match to the selected parameter in the lookup table;

using the closest match to the selected parameter in the lookup table to tune the tunable impedance matching network; and

controlling the ferroelectric capacitor with the digital-to-analog converter.

7. The communication device of claim 6, wherein the parameter is selected to minimize tolerance variations based upon temperature coefficient.

8. The communication device of claim 6, wherein the parameter is selected to minimize tolerance variations based upon component tolerance.

9. The communication device of claim 6, wherein the parameter is selected to minimize tolerance variations based upon tolerance over time.

10. The communication device of claim 6, wherein the tunable impedance matching network includes a rectifier, and an analog-to-digital converter, wherein the rectifier provides a rectified value of a forward RF power to the analog-to-digital converter, and wherein the analog-to-digital converter provides a digital signal representing the rectified value to the controller.

11. The communication device of claim 6, wherein the tunable impedance matching network includes a rectifier, and an analog-to-digital converter, wherein the rectifier provides a rectified value of a reverse RF power to the analog-to-digital converter, and wherein the analog-to-digital converter provides a digital signal representing the rectified value to the controller.

12. A non-transitory computer-readable storage medium comprising computer instructions for adaptively tuning a tunable impedance matching network with a lookup table, the lookup table containing sets of parameters corresponding to matched states for the tunable impedance matching network, the computer instructions responsive to being executed by a processor cause the processor to perform operations comprising:

selecting a parameter from the group consisting of complex reflection coefficients, current drain, incident power, reflected power, control setting of the tunable matching network, temperature, input power level, reliability considerations and linearity considerations;

determining the closest match to the selected parameter in the lookup table;

using the closest match to the selected parameter in the lookup table to tune the tunable impedance matching network, wherein the tunable impedance matching network includes voltage variable capacitors, wherein the voltage variable capacitors ace ferroelectric capacitors; and

controlling the ferroelectric capacitors with digital-to-analog converters.

13. The non-transitory computer-readable storage medium of claim 12, wherein the computer instructions responsive to being executed by the processor cause the processor to perform operations comprising selecting the parameter to minimize tolerance variations based upon temperature coefficient.

14. The non-transitory computer-readable storage medium of claim 12, wherein the computer instructions responsive to being executed by the processor cause the processor to perform operations comprising selecting the parameter to minimize tolerance variations based upon component tolerance.

15. The non-transitory computer-readable storage medium of claim 12, wherein the computer instructions responsive to being executed by the processor cause the processor to perform operations comprising selecting the parameter to minimize tolerance variations based upon tolerance over time.