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

• US 8,395,459 B2
• Filed: 02/29/2012
• Issued: 03/12/2013
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Spears, John H., Smith, Wayne, Sui, Chenggang, Zhu, Yongfei
• Primary Examiner(s): JONES, STEPHEN E
• Application Number:
  US13/408,624
• Publication Number:
  US 20120154069A1
• Time in Patent Office: 377 Days
• Field of Search: 333/17.3, 333/32
• 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. A non-transitory computer-readable storage medium, comprising computer instructions, which when executed by a processor, cause the processor to perform operations comprising:

determining an impedance mismatch at a terminal of a tunable impedance matching network;

determining a closest impedance mismatch in a lookup table, wherein the lookup table comprises a plurality of complex reflection coefficients; and

using at least one of the plurality of complex reflection coefficients in the lookup table which correspond to the determined closest impedance mismatch to tune the tunable impedance matching network.

2. The non-transitory computer-readable storage medium of claim 1, wherein the plurality of complex reflection coefficients are determined by measuring a signal at the tunable impedance matching network for a plurality of impedance loads.

3. The non-transitory computer-readable storage medium of claim 2, wherein the signal is measured while the tunable impedance matching network is in a predetermined state.

4. A method, comprising:

determining an impedance mismatch between input and output terminals of a tunable impedance matching network;

determining a closest impedance mismatch in a lookup table, wherein the lookup table comprises a plurality of complex reflection coefficients determined by measuring a signal at a port of the tunable impedance matching network for a plurality of impedance loads; and

using one or more complex reflection coefficients in the lookup table which correspond to the determined closest impedance mismatch to tune the tunable impedance matching network.

5. The method of claim 4, wherein the lookup table comprises a plurality of matched states of the tunable impedance matching network for each of the plurality of impedance loads.

6. The method of claim 4, comprising tuning the tunable impedance matching network to adaptively match the impedance of an antenna.

7. The method of claim 4, wherein the signal at the port of the tunable impedance matching network for the plurality of impedance loads is measured while the tunable impedance matching network is in a predetermined state.

8. The method of claim 4, wherein the tunable impedance matching network comprises voltage variable capacitors.

9. The method of claim 8, wherein the voltage variable capacitors are voltage-controlled variable ferroelectric capacitors.

10. The method of claim 9, comprising controlling the voltage-controlled variable ferroelectric capacitors with digital to analog converters.

11. The method of claim 4, wherein the tunable impedance matching network comprises one or more variable reactive elements.

12. The method of claim 11, wherein an impedance of the one or more variable reactive elements is controlled by at least one of one or more semiconductor devices, one or more micro-electro-mechanical systems (MEMS) devices, or one or more reactive elements each having a controllable reactance.

13. A method, comprising:

selecting a parameter;

determining a closest match to the selected parameter in a lookup table, wherein the lookup table comprises sets of parameters corresponding to matched states for a tunable impedance matching network for a plurality of impedance loads; and

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

14. The method of claim 13, wherein the lookup table comprises a plurality of matched states of the tunable impedance matching network for each of the plurality of impedance loads.

15. The method of claim 13, wherein a signal at a port of the tunable impedance matching network is measured while the tunable impedance matching network is in a predetermined state.

16. The method of claim 13, wherein the lookup table comprises a sufficient number of matched states such that a transition from one matched state to an adjacent matched state provides a smooth transition.

17. The method of claim 13, comprising selecting the parameter to minimize tolerance variations based upon a temperature coefficient, a component tolerance or a tolerance over time.

18. The method of claim 13, wherein the tunable impedance matching network comprises variable reactive components.

19. The method of claim 18, wherein the variable reactive components are at least one of variable capacitors, variable inductors, or combinations thereof.

20. The method of claim 13, comprising selecting the parameter from a group consisting of complex reflection coefficients, current drain, incident power, reflected power, control setting of a tunable matching network, temperature, input power level, reliability considerations and linearity considerations.