Method and apparatus for tuning antennas in a communication device

• US 9,379,454 B2
• Filed: 11/08/2010
• Issued: 06/28/2016
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Manssen, Keith R., Greene, Matthew R., Rabe, Duane
• Primary Examiner(s): Pan, Yuwen
• Assistant Examiner(s): SHERIF, FATUMA G
• Application Number:
  US12/941,972
• Publication Number:
  US 20120112852A1
• Time in Patent Office: 2,059 Days
• Field of Search: 455/72, 455/73, 455/77, 455/78
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 21/06 Arrays of individually energised antenna units similarly polarised and spaced apart
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• 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
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase

Abstract

A system that incorporates teachings of the present disclosure may include, for example, a process for obtaining a first operational metric for a transmitter of a communication device, determining a range of impedances based on the first operational metric where the range of impedances is associated with an acceptable level of performance for the communication device, obtaining a second operational metric for the transmitter, determining a target impedance within the range of impedances based on the second operational metric, and tuning a first impedance matching network based on the target impedance, where the first impedance matching network is coupled with a first antenna of the communication device, and where the tuning is based on adjusting a first variable component of the first impedance matching network. Additional embodiments are disclosed.

Claims

1. A method comprising:

obtaining an RF voltage at an output of a first tunable matching network of a communication device, wherein the RF voltage is obtained at a transmission frequency of the communication device by a detector, wherein the first tunable matching network has one or more variable capacitors with variable capacitance values, wherein the first tunable matching network is coupled with a first antenna of the communication device;

determining derivative information associated with the RF voltage based on first derivatives of the RF voltage and the variable capacitance values, wherein the first derivatives are calculated according to finite differences of two sequential measurements for each of the RF voltage and the variable capacitance values;

performing first tuning of the first tunable matching network using the derivative information;

determining a predetermined relationship based on a target impedance, a transmit frequency and a receive frequency; and

performing second tuning of a second impedance matching network based on the predetermined relationship, wherein the second impedance matching network is coupled with a second antenna of the communication device, and wherein the second tuning is based on adjusting a second variable component of the second impedance matching network.

2. The method of claim 1, wherein the first antenna is a diversity antenna, wherein the second antenna is a main antenna.

3. The method of claim 1, wherein the obtaining of the RF voltage is performed using a directional coupler.

4. The method of claim 1, wherein the first antenna is a diversity reception antenna.

5. The method of claim 3, wherein the detector is connected in proximity to the first antenna of the communication device without using another detector connected to an input of the second antenna.

6. The method of claim 5, wherein the detector connected in proximity to the first antenna comprises a directional coupler.

7. A method of tuning a communication device, the method comprising:

obtaining an RF voltage at an output of a tunable matching network of the communication device, the RF voltage being obtained at a transmission frequency of the communication device by a detector, the tunable matching network having one or more variable capacitors with variable capacitance values;

determining derivative information associated with the RF voltage based on first derivatives of the RF voltage and the variable capacitance values, wherein the first derivatives are calculated according to finite differences of two sequential measurements for each of the RF voltage and the variable capacitance values; and

tuning the tunable matching network using the derivative information.

8. A non-transitory computer-readable storage medium, comprising computer instructions which, responsive to being executed by a processor of a communication device, cause the processor to perform operations comprising:

obtaining an RF voltage at an output of a tunable matching network of the communication device, the RF voltage being obtained at a transmission frequency of the communication device by a detector, the tunable matching network having one or more variable capacitors with variable capacitance values;

determining derivative information associated with the RF voltage based on first derivatives of the RF voltage and the variable capacitance values, wherein the first derivatives are calculated according to finite differences of two sequential measurements for each of the RF voltage and the variable capacitance values; and

tuning the tunable matching network using the derivative information.

9. The non-transitory computer-readable storage medium of claim 8, wherein the tunable matching network is coupled with a first antenna that is a diversity reception antenna, wherein the communication device comprises a second antenna that is a transmit and receive antenna.

10. The non-transitory computer-readable storage medium of claim 8, wherein the tuning is performed without measuring any parameters at an input of a second antenna.

11. The non-transitory computer-readable storage medium of claim 8, wherein the tuning of the tunable matching network is based in part on current figure of merit that is based on a return loss.

12. The non-transitory computer-readable storage medium of claim 8, wherein the tunable matching network is coupled with a first antenna that is a diversity reception antenna, wherein the communication device comprises a second antenna that is a transmit and receive antenna, and wherein the detector comprises a directional coupler.

13. The non-transitory computer-readable storage medium of claim 8, comprising computer instructions to:

determine a predetermined relationship based on a transmit frequency and a receipt frequency; and

adjust a setting of another variable component of another tunable matching network based on the predetermined relationship, wherein the other tunable matching network is connected to an input of a second antenna and is not connected to an input of a first antenna of the communication device.

14. The non-transitory computer-readable storage medium of claim 8, wherein the tuning of the tunable matching network is based in part on at least one of output power of a transceiver, return loss, received power, current drain or transmitter linearity.

15. The non-transitory computer-readable storage medium of claim 8, wherein the tuning of the tunable matching network is based in part on one or more operational metrics that are obtained using first and second directional couplers, wherein the first directional coupler is connected between a transceiver and a first antenna, and wherein the second directional coupler is connected at a second antenna.

16. The non-transitory computer-readable storage medium of claim 12, comprising computer instructions to switch a transceiver between the first and second antennas based on measurements taken during a receive mode of the communication device.

17. A communication device comprising:

first and second antennas;

a detector;

a first impedance matching network having one or more variable capacitors with variable capacitance values, wherein the first impedance matching network is coupled with the first antenna;

a second impedance matching network coupled with the second antenna, wherein the second impedance matching network comprises a second variable component;

a controller coupled with the first and second impedance matching networks and the detector; and

a memory comprising executable instructions, which, when executed by the controller, cause the controller to perform operations comprising;

obtaining an RF voltage at an output of the first impedance matching network, wherein the RF voltage is obtained at a transmission frequency of the communication device by the detector;

determining derivative information associated with the RF voltage based on first derivatives of the RF voltage and the variable capacitance values, wherein the first derivatives are calculated according to finite differences of two sequential measurements for each of the RF voltage and the variable capacitance values;

performing first tuning of the first impedance matching network using the derivative information;

determining a predetermined relationship based on a target impedance, a transmit frequency and a receive frequency; and

performing second tuning of the second impedance matching network based on the predetermined relationship, wherein the second tuning is based on adjusting the second variable component.

18. The device of claim 17, wherein the obtaining of the RF voltage is performed using a directional coupler.

19. The device of claim 17, wherein the detector is connected in proximity to the first antenna of the communication device without using another detector connected to an input of the second antenna.

20. The device of claim 19, wherein the detector connected in proximity to the first antenna comprises a directional coupler.