System and method for tuning an antenna in a wireless communication device

1. A wireless communication element, comprising:

a receive path configured to receive a first wireless communication signal and convert the first wireless communication signal into a first digital signal based at least on an oscillator signal;

a transmit path configured to convert a second digital signal into a second wireless communication signal based at least on the oscillator signal;

an antenna coupled to the receive path and the transmit path and configured to transmit the second wireless communication signal;

an antenna tuner coupled to the transmit path and the antenna; and

a control path coupled to the antenna and the antenna tuner, the control path configured to:

sense a power transmitted from the transmit path to the antenna;

sense a phase of the power transmitted from the transmit path to the antenna; and

based at least on the sensed power and the send phase, communicate one or more control signals to the antenna tuner for controlling an impedance of the antenna tuner.

2. A wireless communication element according to claim 1 , the antenna tuner comprising one or more variable capacitors, the one or more control signals to the antenna tuner for controlling the capacitances of the one or more variable capacitors.

3. A wireless communication element according to claim 1 , the control path comprising a radio frequency coupler having a coupled port and a terminated port, the radio frequency coupler configured to couple at least a portion of the transmission power of the second wireless communication signal to the coupled port and the terminated port.

4. A wireless communication element according to claim 3 , wherein the coupled port carries a first signal indicative of an incident power transmitted to the antenna and the terminated port carries a second signal indicative of a reflected power reflected by the antenna, and the control path is configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based at least on the first signal and the second signal.

5. A wireless communication element according to claim 4 , the control path further configured to:

downconvert the first signal to a baseband incident power signal having an in-phase channel component and a quadrature channel component;

downconvert the second signal to a baseband reflected power signal having an in-phase channel component and a quadrature channel component; and

communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the baseband incident power signal and the baseband reflected power signal.

6. A wireless communication element according to claim 5 , the control path further configured to:

convert the baseband incident power signal into a digital incident power signal having an in-phase channel component and a quadrature channel component;

convert the baseband reflected power signal into a digital reflected power signal having an in-phase channel component and a quadrature channel component; and

communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the digital incident power signal and the digital reflected power signal.

7. A wireless communication element according to claim 6 , the control path further configured to:

filter the digital incident power signal to produce an averaged digital incident power signal having an in-phase channel component and a quadrature channel component;

filter the digital reflected power signal to produce an averaged digital reflected power signal having an in-phase channel component and a quadrature channel component; and

communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the averaged digital incident power signal and the averaged digital reflected power signal.

8. A wireless communication element according to claim 7 , the control path further configured to:

calculate an incident power based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculate a reflected power based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power and the reflected power.

9. A wireless communication element according to claim 7 , the control path further configured to:

calculate an incident power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculate a reflected power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power phase and the reflected power phase.

10. A control path for control of an antenna tuner, comprising:

a radio frequency coupler having a coupled port and a terminated port, the radio frequency coupler configured to couple at least a portion of a transmission power of a transmission line such that the coupled port carries a first signal indicative of an incident power transmitted to an antenna and the terminated port carries a second signal indicative of a reflected power reflected by the antenna;

an antenna tuner coupled between the transmission line and the antenna; and

a control module configured to communicate the one or more control signals to the antenna tuner for controlling an impedance of the antenna tuner based at least on the incident power, a phase of the incident power, the reflected power, and a phase of the reflected power.

11. A control path according to claim 10 , further comprising:

a downconverter configured to:

downconvert the first signal to a baseband incident power signal having an in-phase channel component and a quadrature channel component; and

downconvert the second signal to a baseband reflected power signal having an in-phase channel component and a quadrature channel component; and

the control module configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the baseband incident power signal and the baseband reflected power signal.

12. A control path according to claim 11 , further comprising:

one or more analog-to-digital converters configured to:

convert the baseband incident power signal into a digital incident power signal having an in-phase channel component and a quadrature channel component; and

convert the baseband reflected power signal into a digital reflected power signal having an in-phase channel component and a quadrature channel component; and

the control module configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the digital incident power signal and the digital reflected power signal.

13. A control path according to claim 12 , further comprising:

one or more filters configured to:

filter the digital incident power signal to produce an averaged digital incident power signal having an in-phase channel component and a quadrature channel component;

filter the digital reflected power signal to produce an averaged digital reflected power signal having an in-phase channel component and a quadrature channel component; and

the control module configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the averaged digital incident power signal and the averaged digital reflected power signal.

14. A control path according to claim 13 , further comprising:

a power measurement module configured to:

calculate an incident power based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculate a reflected power based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

the control module configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power and the reflected power.

15. A control path according to claim 13 , further comprising:

a phase measurement module configured to:

calculate an incident power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculate a reflected power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

the control module configured to communicate the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power phase and the reflected power phase.

16. A method, comprising:

coupling a radio frequency coupler to a transmission line such that a coupled port of the radio frequency coupler carries a first signal indicative of an incident power transmitted to an antenna and a terminated port of the radio frequency coupler carries a second signal indicative of a reflected power reflected by the antenna; and

communicating the one or more control signals to an antenna tuner coupled between the transmission line and the antenna;

controlling an impedance of the antenna tuner based at least on the incident power, a phase of the incident power, the reflected power, and a phase of the reflected power.

17. A method according to claim 16 , further comprising:

downconverting the first signal to a baseband incident power signal having an in-phase channel component and a quadrature channel component;

downconverting the second signal to a baseband reflected power signal having an in-phase channel component and a quadrature channel component; and

communicating the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the baseband incident power signal and the baseband reflected power signal.

18. A method according to claim 17 , further comprising:

converting the baseband incident power signal into a digital incident power signal having an in-phase channel component and a quadrature channel component;

converting the baseband reflected power signal into a digital reflected power signal having an in-phase channel component and a quadrature channel component; and

communicating the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the digital incident power signal and the digital reflected power signal.

19. A method according to claim 16 , further comprising:

calculating an incident power based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculating a reflected power based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

communicating the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power and the reflected power.

20. A method according to claim 16 , further comprising:

calculating an incident power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital incident power signal;

calculating a reflected power phase based at least on the in-phase channel component and the quadrature channel component of the averaged digital reflected power signal; and

communicating the one or more control signals to the antenna tuner for controlling the impedance of the antenna tuner based on at least on the incident power phase and the reflected power phase.