METHODS AND APPARATUS TO CONTROL MUTUAL COUPLING BETWEEN ANTENNAS

• US 20140011460A1
• Filed: 07/06/2012
• Published: 01/09/2014
• Est. Priority Date: 07/06/2012
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Ali, Shirook M., Deforge, John Bradley
• Granted Patent: US 9,853,363 B2
• Time in Patent Office: Days
• US Class Current: 455/75
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/13 of power amplifiers, e.g. gain or non-linearity
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements

Abstract

A system that incorporates teachings of the subject disclosure may include, for example, a method for comparing a received signal from a first antenna to a reference signal transmitted by a second antenna, determining from the comparison one or more compensation parameters, and tuning a compensation circuit according to the one or more compensation parameters, where the one or more compensations parameters configure the compensation circuit to reduce mutual coupling between the first and second antennas. Other embodiments are disclosed.

Claims

1. A communication device, comprising:

a first antenna;

a second antenna;

a tunable compensation circuit;

a first circuit coupled to the first antenna;

a second circuit coupled to the second antenna; and

a controller coupled to the tunable compensation circuit, and the first and second circuits, wherein responsive to executing computer instructions, the controller performs operations comprising;

causing a transmission of a reference signal from the first antenna;

receiving a signal from the second antenna, wherein the signal is associated with the reference signal transmitted by the first antenna;

determining from the received signal one or more compensation parameters; and

tuning the tunable compensation circuit according to the one or more compensation parameters, wherein the one or more compensation parameters set a variable impedance or variable circuit configuration of the tunable compensation circuit to reduce the mutual coupling between the first and second antennas.

2. The communication device of claim 1, wherein the first circuit comprises a radio frequency transmitter portion, and wherein the second circuit comprises a radio frequency receiver portion.

3. The communication device of claim 1, wherein the tunable compensation circuit is connected to a first feed point of the first antenna, a second feed point of the second antenna, or both.

4. The communication device of claim 1, wherein the tunable compensation circuit is connected to a first structural element of the first antenna, a second structural element of the second antenna, or both.

5. The communication device of claim 1, wherein the tunable compensation circuit comprises a parasitic antenna coupled to one or more tunable elements for reducing mutual coupling between the first and second antennas.

6. The communication device of claim 5, wherein the parasitic antenna is connected to a first structure of the first antenna, a second structure of the second antenna, or both.

7. The communication device of claim 5, wherein the parasitic antenna is not connected to a first structural element of the first antenna, a second structural element of the second antenna, or both.

8. The communication device of claim 4, wherein the parasitic antenna is coupled to ground.

9. The communication device of claim 1, wherein the determining from the signal the one or more compensation parameters comprises:

receiving from the first circuit information relating to the reference signal;

comparing the received information to the received signal; and

determining the one or more compensation parameters from the comparison.

10. The communication device of claim 1, comprising a switch, wherein the first and second circuits are coupled to the first and second antennas by way of the switch, and wherein the causing of the transmission of the reference signal from the first antenna comprises causing the switch to couple one of the first circuit or the second circuit to the first antenna to transmit the reference signal from the first antenna.

11. The communication device of claim 1, wherein the determining from the signal the one or more compensation parameters comprises:

supplying from the first circuit to the second circuit information relating to the reference signal;

comparing the received information to the received signal; and

determining the one or more compensation parameters from the comparison.

12. The communication device of claim 1, comprising a sensor, wherein the receiving of the signal comprises receiving the signal from the sensor, and wherein the determining from the signal the one or more compensation parameters comprises:

determining a backscattered signal from a comparison of the received signal to the reference signal; and

determining the one or more compensation parameters from the backscattered signal.

13. The communication device of claim 12, wherein the sensor comprises one of a circulator device or a directional coupler, and wherein the sensor supplies to the controller analog or digital signals representative of the received signal.

14. The communication device of claim 12, wherein the determining of the backscattered signal comprises:

sensing by way of the sensor a reflected signal;

substantially removing the reflected signal from the received signal to generated an updated received signal; and

determining the backscattered signal from the updated received signal.

15. The communication device of claim 1, wherein the one or more compensation parameters tune one or more tunable elements of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the one or more tunable elements comprise at least one fixed reactive element controlled by at least one semiconductor device to produce a variable reactance.

16. The communication device of claim 1, wherein the one or more compensation parameters tune one or more tunable elements of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the one or more tunable elements comprise at least one fixed reactive element controlled by at least one micro-electro-mechanical system device to produce a variable reactance.

17. The communication device of claim 1, wherein the one or more compensation parameters tune one or more tunable elements of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the one or more tunable elements comprise at least one variable reactive element controlled by at least one micro-electro-mechanical system device to produce a variable reactance.

18. The communication device of claim 1, wherein the one or more compensation parameters tune one or more tunable elements of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the one or more tunable elements comprise at least one variable reactive element controlled by a bias signal that varies a dielectric constant of the variable reactive element to produce a variable reactance.

19. The communication device of claim 1, wherein the one or more compensation parameters set the variable circuit configuration of the tunable compensation circuit, and wherein the variable circuit configuration comprises one of a configurable transmission line, a configurable parasitic antenna, a configurable reactive component, or combinations thereof.

20. The communication device of claim 1, wherein the communication device is a portable communication device, and wherein the tunable compensation circuit comprises one or more variable capacitors, one or more variable inductors, or combinations thereof.

21. The communication device of claim 1, wherein the one or more compensation parameters include one of one or more binary signals, one or more bias signals, or both.

22. The communication device of claim 1, wherein the determining from the received signal the one or more compensation parameters comprises:

determining a mode of operation of the communication device; and

determining the one or more compensation parameters from the mode of operation of the communication device and the received signal.

23. The communication device of claim 1, wherein the first antenna is coupled to a first matching network and the second antenna is coupled to a second matching network, and wherein one of the first matching network, the second matching network or both includes a fixed-impedance matching circuit or a tunable impedance matching circuit.

24. The communication device of claim 1, wherein the first antenna is not coupled to a first matching network and the second antenna is not coupled to a second matching network.

25. The communication device of claim 1, wherein the operations performed by the controller further comprise determining from a look-up table according to a mode of operation of the communication device one of an adjustment to adjust the received signal for determining the one or more compensation parameters from the adjusted signal, one or more initial parameter settings for a first matching network coupled to the first antenna, one or more initial parameter settings for a second matching network coupled to the second antenna, one or more initial parameter settings for the tunable compensation circuit, or combinations thereof.

26. A computer readable storage medium, comprising computer instructions, which when executed by a processor, cause the processor to perform operations comprising:

receiving a signal from a first antenna, wherein the signal is associated with a reference signal transmitted by a second antenna;

determining from the received signal one or more compensation parameters; and

adjusting a compensation circuit including a configurable circuit according to the one or more compensation parameters, wherein the one or more compensation parameters configure the compensation circuit to reduce mutual coupling between the first and second antennas.

27. The computer readable storage medium of claim 26, wherein the adjusting includes using the compensation parameters to set the configuration circuit to cause one of a configurable transmission line, a configurable parasitic antenna, a configurable reactive component, or combinations thereof to reduce the mutual coupling between the first and second antennas.

28. The computer readable storage medium of claim 26, wherein the determining from the received signal the one or more compensation parameters comprises determining from a look-up table according to a mode of operation of the communication device the one or more compensation parameters.

29. A method, comprising:

comparing a received signal from a first antenna to a reference signal transmitted by a second antenna;

determining from the comparison one or more compensation parameters; and

tuning a compensation circuit according to the one or more compensation parameters, wherein the one or more compensations parameters configure the compensation circuit to reduce mutual coupling between the first and second antennas.

30. The method of claim 29, wherein the compensation circuit comprises one or more tunable reactive elements, wherein the one or more tunable reactive elements comprise one or more variable capacitors, one or more variable inductors, or combinations thereof.

31. The method of claim 29, wherein the one or more compensation parameters reduce a correlation between the first and second antennas.

32. The method of claim 29, wherein the determining from the received signal the one or more compensation parameters comprises determining from a look-up table according to a mode of operation of the communication device the one or more compensation parameters.