Methods and apparatus to control mutual coupling between antennas

Patent metadata

Field	Value
Publication number	US-9853363-B2
Application number	US-201213542686-A
Country	US
Kind code	B2
Filing date	Jul 6, 2012
Priority date	Jul 6, 2012
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

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.

First claim

What is claimed is:

1. A communication device, comprising:
a first antenna;
a first matching network coupled to the first antenna, the first matching network including a first tunable reactance;
a second antenna;
a second matching network coupled to the second antenna, the second matching network including a second tunable reactance;
a tunable compensation circuit comprising a parasitic antenna element coupled to a tunable reactive circuit, wherein the parasitic antenna element absorbs radiation from the first antenna, the second antenna or both, wherein the radiation absorbed by the tunable compensation circuit, by way of the parasitic antenna element, reduces a mutual coupling between the first antenna and the second antenna;
a first circuit coupled to the first antenna;
a second circuit coupled to the second antenna; and
a controller in communication with the tunable compensation circuit, the first matching network and the second matching network, the first and second circuits, wherein responsive to executing instructions, the controller facilitates performance of operations comprising:
adjusting the first and second tunable reactances to perform impedance matching for the first and second antennas;
facilitating a transmission of a reference signal from the second antenna resulting from connecting the first circuit to the second antenna;
receiving a signal at the first antenna to obtain a received signal, wherein the signal is associated with the reference signal transmitted from the second antenna;
determining a backscatter current from a comparison of the received signal to the reference signal; and
responsive to the backscatter current exceeding a backscatter current threshold:
tuning the tunable compensation circuit by setting a variable impedance or variable circuit configuration of the tunable compensation circuit to reduce the mutual coupling between the first and second antennas,
wherein the tuning of the tunable compensation circuit comprises controlling the tunable reactive circuit to adjust a resonant frequency of the parasitic antenna element, thereby reducing the mutual coupling between the first antenna and the second antenna, and is performed responsive to a determination that the adjusting of the first and second tunable reactances satisfies an impedance matching threshold.

2. The communication device of claim 1 , further comprising:
a cross-coupler coupled between the first and second antennas and the first and second circuits and in communication with the controller,
wherein the first circuit comprises a first radio frequency transceiver comprising a first transmitter portion and a first receiver portion,
wherein the second circuit comprises a second radio frequency receiver portion comprising a second transmitter portion and a second receiver portion, and
wherein the cross-coupler, responsive to receiving a signal from the controller, temporarily couples the first transmitter portion to the second antenna to facilitate the transmission of the reference signal from the second antenna.

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 reactive circuit is controlled to produce a phase difference of about 180 degrees between the parasitic antenna element and the first antenna, the second antenna or both.

6. The communication device of claim 5 , wherein the parasitic antenna element 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 element 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 5 , wherein the parasitic antenna element is coupled to ground via the tunable reactive circuit.

9. The communication device of claim 1 , wherein the operations further comprise:
receiving, from the first circuit, information to obtain received information relating to the reference signal;
comparing the received information to the received signal to obtain a comparison; and
determining a compensation parameter from the comparison, wherein the tunable compensation circuit is tuned in accordance with the compensation parameter.

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 facilitating 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 operations further comprise:
supplying, from the first circuit to the second circuit, information to obtain supplied information relating to the reference signal;
comparing the supplied information to the received signal to obtain a comparison; and
determining a compensation parameter from the comparison, wherein the tunable compensation circuit is tuned in accordance with the compensation parameter.

12. The communication device of claim 1 , comprising a sensor, wherein the receiving of the signal comprises receiving the signal from the sensor.

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 backscatter current comprises:
sensing by way of the sensor a reflected signal;
substantially removing the reflected signal from the received signal to generate an updated received signal; and
determining the backscatter current from the updated received signal.

15. The communication device of claim 1 , wherein a compensation parameter determined from the backscatter current tunes a tunable element of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the tunable element comprises 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 a compensation parameter determined from the backscatter current tunes a tunable element of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the tunable element comprises 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 a compensation parameter determined from the backscatter current tunes a tunable element of the tunable compensation circuit to control the variable impedance of the tunable compensation circuit, and wherein the tunable element comprises 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 , wherei

Assignees

• Ali Shirook M
• Deforge John Bradley
• Blackberry Ltd

Inventors

• Ali Shirook M
• Deforge John Bradley

Classifications

• H04B17/221

  of receiver antennas, e.g. as to amplitude or phase · CPC title

• H04B17/12

  of transmit antennas, e.g. of the amplitude or phase · CPC title

• H01Q1/523

  between antennas of an array · CPC title

• H04B17/21

  for calibration; for correcting measurements · CPC title

• H01Q1/243

  with built-in antennas · CPC title