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

• US 8,072,285 B2
• Filed: 09/24/2008
• Issued: 12/06/2011
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Paratek Microwave Incorporated (Blackberry Limited)
• Inventors: Spears, John H., Smith, Wayne E., Sui, Chenggang, Zhu, Yongfei
• Primary Examiner(s): JONES, STEPHEN E
• Application Number:
  US12/236,662
• Publication Number:
  US 20100073103A1
• Time in Patent Office: 1,168 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. A method for generating a look-up table relating a plurality of complex reflection coefficients to a plurality of matched states for a tunable impedance matching network, said method comprising the steps of:

measuring a signal at a port of a tunable impedance matching network to determine a plurality of complex reflection coefficients resulting from a plurality of impedance loads while the tunable impedance matching network is in a predetermined state;

determining a plurality of matched states of the tunable impedance matching network for each of the plurality of impedance loads; and

storing the plurality of determined matched states as a look-up table in a memory device.

2. The method for generating a look-up table in accordance with claim 1 further comprising the step of:

interpolating the measured complex reflection coefficients and the determined matching states into a set of complex reflection coefficients with predetermined step sizes.

3. The method for generating a look-up table in accordance with claim 1 further comprising the step of:

selecting the predetermined state used in measuring the complex reflection coefficients to minimize tolerance variations based upon temperature coefficient, component tolerance or tolerance over time.

4. The method for generating a look-up table in accordance with claim 1 further comprising the step of:

reiterating the steps of claim 1 for different frequency bands or for different frequencies.

5. The method of claim 1, wherein an antenna is coupled to the tunable impedance matching network, and wherein the method comprises:

measuring an impedance of the antenna;

selecting a matching state from the look-up table according to the measured impedance of the antenna; and

tuning the tunable impedance matching impedance network according to the selected matching state.

11. The method for generating a look-up table in accordance with claim 6 further comprising the step of:

reiterating the steps of claim 5 for different frequency bands or for different frequencies.

6. A method for generating a look-up table relating a set of measured parameters to a set of matched states for a tunable impedance matching network, said method comprising the steps of:

measuring a signal at a port of the tunable impedance matching network to determine a set of parameters associated with a plurality of impedance loads while the tunable impedance matching network is in a predetermined state;

determining a matched state of the tunable impedance matching network for each of the plurality of impedance loads; and

storing the plurality of determined matched states as a look-up table in a storage device.

7. The method for generating a look-up table in accordance with claim 6 wherein the set of measured parameters is selected 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.

8. The method for generating a look-up table in accordance with claim 6 further comprising the step of:

providing a sufficient number of matched states such that a transition from one matched state to an adjacent matched state provides a smooth transition.

9. The method for generating a look-up table in accordance with claim 6 further comprising the step of:

interpolating the measured set of parameters and the determined matching states into a set of complex parameters with predetermined step sizes.

10. The method for generating a look-up table in accordance with claim 6 further comprising the step of:

selecting the predetermined state used in measuring the set of parameters to minimize tolerance variations based upon temperature coefficient, component tolerance or tolerance over time.

12. The method of claim 6, wherein an antenna is coupled to the tunable impedance matching network, and wherein the method comprises:

measuring an impedance of the antenna;

selecting a matching state from the look-up table according to the measured impedance of the antenna; and

tuning the tunable impedance matching impedance network according to the selected matching state.