Method and apparatus for tuning antennas in a communication device

• US 9,263,806 B2
• Filed: 04/03/2013
• Issued: 02/16/2016
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Manssen, Keith Ronald, Greene, Matthew Russell, Rabe, Duane
• Primary Examiner(s): Takaoka, Dean
• Assistant Examiner(s): Wong, Alan
• Application Number:
  US13/856,075
• Publication Number:
  US 20130222205A1
• Time in Patent Office: 1,049 Days
• Field of Search: 333/17.3, 333/32
• 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 matching network for a communication device having first and second antennas, where the matching network includes a first variable component connectable and a detector. The first variable component can be connectable along a first path between the first antenna and a front end module of the communication device, where the first antenna is configured for transmit and receive operation. The detector can be connectable along a second path between the second antenna and the front end module of the communication device, where the detector obtains an RF voltage associated with the second path, where the second antenna is configured for a diversity receive operation, and where the first variable component is adjusted based on the detected RF voltage to tune the matching network. Additional embodiments are disclosed.

Claims

1. A mobile communication device, comprising:

an antenna;

a matching circuit coupled with the antenna, the matching circuit including one or more variable reactance elements with variable reactance values; and

a controller coupled with the matching circuit, wherein the controller obtains an RF voltage at an output of the matching circuit, wherein the controller determines derivative information associated with the RF voltage by calculating a finite difference of two sequential measurements associated with the variable reactance values, and wherein the controller tunes the matching circuit using the derivative information.

2. The mobile communication device of claim 1, wherein the RF voltage is obtained at a transmission frequency of the mobile communication device.

3. The mobile communication device of claim 1, wherein the RF voltage is obtained using a log detector.

4. The mobile communication device of claim 1, wherein the derivative information comprises first and second derivatives.

5. The mobile communication device of claim 1, wherein the controller tunes the matching circuit without additional information using only information obtained by a detector at an output of the antenna.

6. The mobile communication device of claim 1, wherein the antenna is a transmit/receive antenna in a diversity antenna system.

7. The mobile communication device of claim 1, comprising a detector coupled with an output of a second antenna in a multiple antenna system.

8. The mobile communication device of claim 1, wherein the tuning of the matching circuit is performed for duplex operation of the communication device using the derivative information associated with the RF voltage.

9. The mobile communication device of claim 1, wherein the tuning of the matching circuit is performed for a receive operation using the derivative information associated with the RF voltage.

10. A matching network for a communication device, the matching network comprising:

a first matching circuit coupled with a main antenna, the matching circuit comprising one or more variable reactance elements with variable reactance values;

a detector coupled with a diversity antenna; and

a controller coupled with the first matching circuit, wherein the controller obtains an RF voltage for the diversity antenna from the detector, wherein the controller determines derivative information associated with the RF voltage based on derivatives of the RF voltage and the variable reactance values, wherein the controller tunes the first matching circuit using the derivative information, wherein the RF voltage is obtained during a transmit mode of the communication device utilizing first tuning values based on the derivative information, and wherein the controller applies an offset to the first tuning values for tuning for a receive mode of the communication device.

11. The matching network of claim 10, wherein the controller determines the derivative information by calculating a finite difference of two sequential measurements associated with the variable reactance values and wherein the offset is calculated based on a difference in operational frequencies during the transmit and receive modes.

12. The matching network of claim 10, wherein the derivative information comprises first and second derivatives.

13. The matching network of claim 10, wherein the controller is configured to tune the matching circuit without additional measured information using only measured information obtained by the detector.

14. The matching network of claim 10, wherein a second matching circuit is coupled with the diversity antenna, wherein the controller is coupled with the second matching circuit, and wherein the controller tunes the second matching circuit using the derivative information.

15. A method of tuning a communication device having first and second antennas, the method comprising:

selectively switching a detector between first and second paths to obtain first and second operational metrics, respectively, the first path being between the first antenna and a front end module of the communication device, the first path comprising a first variable reactance component, the second path being between the second antenna and the front end module of the communication device, the second path comprising a second variable reactance component;

obtaining the first and second operational metrics during a transmit mode of the communication device;

determining a tuning offset according to a difference in operational frequencies between the transmit mode and a receive mode; and

independently tuning the first and second antennas for the receive mode by adjusting the first and second variable reactance components based on the tuning offset and the first and second operational metrics, respectively.

16. The method of claim 15, wherein one of the first and second antennas is a diversity reception antenna.

17. The method of claim 15, wherein the first and second variable reactance components comprise a semi-conductor switch, a voltage tunable capacitor, or a combination thereof.

18. The method of claim 15, wherein the first and second antennas are tuned independently without detecting measurements at inputs of the first and second antennas.

19. The method of claim 15, wherein the selective switching is performed using a double-pole double-throw RF switch.

20. The method of claim 15, wherein the selective switching of the detector is performed by selectively establishing the first and second paths using a switching element.