Apparatus and methods for tuning antenna impedance using transmitter and receiver parameters

• US 20040009754A1
• Filed: 07/12/2002
• Published: 01/15/2004
• Est. Priority Date: 07/12/2002
• Status: Active Grant

• Current Assignee: Sony Ericsson Mobile Communications (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications (Sony Group Corp.)
• Inventors: Smith, Edward Lee Jr.
• Granted Patent: US 6,993,297 B2
• Time in Patent Office: Days
• US Class Current: 455/82
• CPC Class Codes: H03F 2200/504 the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
• 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

Abstract

According to some embodiments of the present invention, an impedance transformation circuit is provided for use with a transmitter, a receiver, and an antenna. The transmitter may provide transmission signals for transmission by the antenna. The antenna may provide received signals having an associated signal parameter to the receiver. The impedance transformation circuit includes an impedance adjusting circuit and a controller. The impedance adjusting circuit is connected between the antenna, the receiver, and the transmitter. The impedance adjusting circuit is configured to change an impedance difference presented between at least one of: 1) the transmitter and the antenna, and 2) the antenna and the receiver, in response to a control signal. The controller generates the control signal to change the presented impedance difference in response to a signal parameter.

Claims

1. An impedance transformation circuit for use with a transmitter, a receiver, and an antenna, the transmitter providing a transmission signal for transmission by the antenna, the antenna providing a received signal having an associated signal parameter to the receiver, the impedance transformation circuit comprising:

an impedance adjusting circuit between the antenna and receiver and transmitter, the impedance adjusting circuit being configured to change an impedance difference presented between at least one of;

     1) the transmitter and the antenna, and

     2) the antenna and the receiver, in response to a control signal; and

a controller that generates the control signal to change the presented impedance difference in response to the signal parameter.

2. The impedance transformation circuit of claim 1, wherein the impedance adjusting circuit is configured to change an impedance difference presented between the transmitter and the antenna and between the antenna and the receiver, in response to the control signal.

3. The impedance transformation circuit of claim 1, wherein the signal parameter is indicative of an amount of power reflected in the received signal.

4. The impedance transformation circuit of claim 3, wherein the controller modifies the control signal to cause the impedance adjusting circuit to reduce the presented impedance difference between the antenna and the receiver if the amount of reflected power does not satisfy a threshold value.

5. The impedance transformation circuit of claim 4, wherein the controller modifies the control signal to reduce the presented impedance difference between the antenna and the receiver to about 0.

6. The impedance transformation circuit of claim 3, wherein the signal parameter is indicative of a ratio of reflected power to non-reflected power of the received signal.

7. The impedance transformation circuit of claim 3, wherein the controller modifies the control signal to cause the impedance adjusting circuit to reduce the presented impedance difference between the transmitter and the antenna if the amount of reflected power satisfies a threshold value.

8. The impedance transformation circuit of claim 1, wherein the controller is configured to receive an indication of an amount of power reflected in the transmission signal and is operative to modify the control signal to change the presented impedance difference between the receiver and the antenna in response to the amount of reflected power in the transmission signal.

9. The impedance transformation circuit of claim 1, wherein the signal parameter is indicative of a received signal strength of the received signal.

10. The impedance transformation circuit of claim 9, wherein the controller modifies the control signal to reduce the presented impedance difference between the transmitter and the antenna if the received signal strength satisfies a threshold value.

11. The impedance transformation circuit of claim 9, wherein the controller modifies the control signal to reduce the presented impedance difference between the antenna and the receiver if the received signal strength does not satisfy a threshold value.

12. The impedance transformation circuit of claim 9, wherein:

the controller is further configured to modify the control signal to reduce the presented impedance difference between the transmitter and the antenna when the received signal strength satisfies a threshold value, and to modify the control signal to reduce the presented impedance difference between the antenna and the receiver when the received signal strength does not satisfy a threshold value.

13. The impedance transformation circuit of claim 1, wherein the signal parameter is indicative of a bit error rate of the received signal.

14. The impedance transformation circuit of claim 13, wherein the controller modifies the control signal to reduce the presented impedance difference between the antenna and the receiver if the bit error rate does not satisfy a threshold value.

15. The impedance transformation circuit of claim 13, wherein the controller modifies the control signal to reduce the presented impedance difference between the transmitter and the antenna if the bit error rate satisfies a threshold value.

16. The impedance transformation circuit of claim 13, wherein:

the controller modifies the control signal to reduce the presented impedance difference between the antenna and the receiver when the bit error rate does not satisfy a threshold value, and modifies the control signal to reduce the presented impedance difference between the transmitter and the antenna when the bit error rate satisfies a threshold value.

17. The impedance transformation circuit of claim 1, wherein the signal parameter is indicative of when the receiver is actively receiving signals.

18. The impedance transformation circuit of claim 17, wherein the controller modifies the control signal to reduce the presented impedance difference between the antenna and the receiver if the receiver is actively receiving signals.

19. The impedance transformation circuit of claim 1, wherein the signal parameter is indicative of when the transmitter is actively transmitting signals.

20. The impedance transformation circuit of claim 19, wherein the controller is configured to modify the control signal to reduce the presented impedance difference between the transmitter and the antenna if the transmitter is actively transmitting signals.

21. The impedance transformation circuit of claim 1, wherein:

the signal parameter is indicative of when the receiver is actively receiving signals and the transmitter is actively transmitting signals;

the controller is configured to modify the control signal to reduce the presented impedance difference between the transmitter and the antenna when the transmitter is actively transmitting signals and the receiver is not actively receiving signals, and to modify the control signal to reduce the presented impedance difference between the antenna and the receiver when the transmitter is not active and the receiver is active.

22. A method of operating an antenna tuner used with a transmitter, a receiver, and an antenna, the method comprising:

sensing a signal parameter associated with a received signal provided by the antenna to the receiver; and

adjusting an impedance presented between at least one of;

     1) the transmitter and the antenna, and

     2) the antenna and the receiver, in response to the sensed parameter.

23. The method of claim 22, wherein the sensed signal parameter is indicative of an amount of power reflected in the received signal provided between the antenna and the receiver.

24. The method of claim 23, wherein adjusting an impedance comprises reducing the presented impedance difference between the antenna and the receiver when the amount of reflected power does not satisfy a threshold value.

25. The method of claim 23, wherein the sensed signal parameter is indicative of a ratio of reflected power to non-reflected power.

26. The method of claim 23, wherein adjusting an impedance comprises reducing the presented impedance difference between the transmitter and the antenna when the amount of reflected power satisfies a threshold value.

27. The method of claim 22, wherein:

the sensed signal parameter is further indicative of an amount of power reflected in a signal provided by the transmitter to the antenna for transmission; and

adjusting an impedance comprises changing the presented impedance difference between the receiver and the antenna in response to the amount of reflected power.

28. The method of claim 22, wherein the sensed parameter is indicative of a received signal strength of the received signal.

29. The method of claim 28, wherein adjusting an impedance comprises reducing the presented impedance difference between the transmitter and the antenna when the sensed parameter indicates that the received signal strength satisfies a threshold value.

30. The method of claim 28, wherein adjusting an impedance comprises reducing the presented impedance difference between the receiver and the antenna when the sensed parameter indicates that the received signal strength does not satisfy a threshold value.

31. The method of claim 28, wherein adjusting an impedance comprises:

reducing the presented impedance difference between the transmitter and the antenna when the sensed parameter indicates that the received signal strength satisfies a threshold value; and

reducing the presented impedance difference between the receiver and the antenna when the sensed parameter indicates that the received signal strength is does not satisfy a threshold value.

32. The method of claim 22, wherein the sensed parameter is indicative of a bit error rate of the second information signal.

33. The method of claim 32, wherein adjusting an impedance comprises:

reducing the presented impedance difference between the transmitter and the antenna when the sensed parameter indicates that the bit error rate satisfies a threshold value.

34. The method of claim 32, wherein adjusting an impedance comprises:

reducing the presented impedance difference between the receiver and the antenna when the sensed parameter indicates that the bit error rate does not satisfy a threshold value.

35. The method of claim 32, wherein adjusting an impedance comprises:

reducing the presented impedance difference between the transmitter and the antenna when the sensed parameter indicates that the bit error rate satisfies a threshold value; and

reducing the presented impedance difference between the receiver and the antenna when the sensed parameter indicates that the bit error rate does not satisfy a threshold value.

36. The method of claim 22, wherein:

sensing a signal parameter comprises sensing a parameter indicative of when the receiver is actively receiving signals; and

adjusting an impedance comprises reducing the presented impedance between the receiver and the antenna when the receiver is actively receiving signals.

37. The method of claim 22, wherein:

sensing a signal parameter comprises sensing a parameter indicative of when the transmitter is actively providing signals to the antenna for transmission; and

adjusting an impedance comprises reducing the presented impedance between the transmitter and the antenna when the transmitter is actively providing signals to the antenna for transmission.

38. The method of claim 22, wherein:

sensing a signal parameter comprises when the transmitter is actively providing signals to the antenna for transmission and when the receiver is actively receiving signals; and

adjusting an impedance comprises reducing the presented impedance between the transmitter and the antenna when the transmitter is active and the receiver is not active and reduces the presented impedance between the receiver and the antenna when the receiver is active and the transmitter is not active.