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

• US 8,957,742 B2
• Filed: 02/08/2013
• Issued: 02/17/2015
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Spears, John Hanford, Smith, Wayne Eric, Sui, Chenggang, Zhu, Yongfei
• Primary Examiner(s): JONES, STEPHEN E
• Application Number:
  US13/762,607
• Publication Number:
  US 20130147681A1
• Time in Patent Office: 739 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 communication device, comprising:

a power amplifier;

an antenna coupled with the power amplifier;

a tunable impedance matching network coupled between the power amplifier and the antenna, where the tunable impedance matching network includes one or more tunable reactive elements;

a detector coupled between the tunable impedance matching network and the power amplifer;

a memory that stores instructions and a look-up table; and

a processor coupled to the memory, the detector and the tunable impedance matching network, wherein responsive to executing the instructions, the processor performs operations comprising;

determining forward and reverse power at a terminal of the tunable impedance matching network via the detector;

determining, at the terminal based on the forward and reverse power, an impedance mismatch caused by a change in impedance of the antenna;

locating an impedance mismatch entry in the lookup table that approximates the impedance mismatch, wherein the lookup table comprises a plurality of complex reflection coefficients predetermined by measuring a signal at the terminal of the tunable impedance matching network for a plurality of impedance loads of the antenna; and

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

2. The communication device of claim 1, wherein the lookup table comprises a plurality of matched states of the tunable impedance matching network for each of the plurality of impedance loads.

3. The communication device of claim 1, wherein the operations further comprise tuning the tunable impedance matching network using the one or more complex reflection coefficients to adaptively match the impedance of the antenna.

4. The communication device of claim 1, wherein the signal is measured at the terminal of the tunable impedance matching network while the tunable impedance matching network is in a predetermined state.

5. The communication device of claim 1, wherein the communication device is a portable communication device.

6. The communication device of claim 1, wherein the one or more tunable reactive elements comprise one or more variable capacitors.

7. The communication device of claim 6, wherein the one or more variable capacitors comprise one or more voltage-controlled variable ferroelectric capacitors.

8. The communication device of claim 7, further comprising digital to analog converters, wherein the operations further comprise controlling the one or more voltage-controlled variable ferroelectric capacitors with digital to analog converters.

9. The communication device of claim 1, wherein the one or more tunable reactive elements comprise one or more micro-electro-mechanical systems (MEMS) devices.

10. The communication device of claim 9, wherein the one or more tunable reactive elements comprises one of one or more semiconductor devices.

11. A communication device, comprising:

an antenna;

a tunable impedance matching network coupled with the antenna, where the tunable impedance matching network includes one or more tunable reactive elements;

a detector coupled with the tunable impedance matching network;

a memory that stores instructions and a look-up table; and

a processor coupled to the memory, the detector and the tunable impedance matching network, wherein responsive to executing the instructions, the processor performs operations comprising;

determining one or more parameters at a terminal of the tunable impedance matching network via the detector;

determining, at the terminal according to the one or more parameters and according to band information, an impedance mismatch caused by a change in impedance of the antenna;

locating an impedance mismatch entry in the lookup table that approximates the impedance mismatch, wherein the lookup table comprises a plurality of complex reflection coefficients predetermined by measuring a signal at the terminal of the tunable impedance matching network for a plurality of impedance loads of the antenna; and

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

12. A communication device, comprising:

an antenna;

a tunable impedance matching network coupled with the antenna, where the tunable impedance matching network includes one or more tunable reactive elements;

a detector coupled with the tunable impedance matching network;

a memory that stores instructions and a look-up table; and

a processor coupled to the memory, the detector and the tunable impedance matching network, wherein responsive to executing the instructions, the processor performs operations comprising;

determining one or more parameters at a terminal of the tunable impedance matching network via the detector;

determining, at the terminal according to the one or more parameters and according to band information, an impedance mismatch caused by a change in impedance of the antenna;

locating an impedance mismatch entry in the lookup table that approximates the impedance mismatch, wherein the lookup table comprises a plurality of complex reflection coefficients indexed based on frequency band, magnitude and phase and that are predetermined by measuring a signal at the terminal of the tunable impedance matching network for a plurality of impedance loads of the antenna; and

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