Adaptive antenna tuning during transmission

Patent metadata

Field	Value
Publication number	US-10784573-B2
Application number	US-201816156351-A
Country	US
Kind code	B2
Filing date	Oct 10, 2018
Priority date	Oct 10, 2018
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

A system and method of adaptively tuning an antenna of a wireless device including detecting a reflected electrical signal from the antenna during transmission of a wireless signal, converting the reflected electrical signal into at least one parameter indicative of its strength, and adjusting, based on the at least one parameter, a tune value to adjust a matching network during the transmission of the wireless signal to reduce the strength of the reflected electrical signal. The reflected electrical signal may be converted to a corresponding power value, and the tune value may be repeatedly adjusted by an incremental amount or according to a binary search method or the like to reduce the power level of the reflected electrical signal. The reflected electrical signal may be demodulated into demodulated information used to determine an optimal transfer function of the matching network and the tune value may be adjusted accordingly.

First claim

The invention claimed is:

1. A wireless device with adaptive antenna tuning, comprising:
an antenna;
a matching network coupled to said antenna and having a tuning input for receiving a tune signal for tuning said antenna;
an electrical communication path coupled to said matching network for conveying electrical signals to and from said antenna;
a directional coupler interfacing said electrical communication path to detect a reflected electrical signal from said antenna during transmission of a wireless signal;
a detector comprising a measurement receiver that demodulates said reflected electrical signal into demodulated information; and
a controller that uses said demodulated information to adjust said tune signal to reduce said strength of said reflected electrical signal.

2. The wireless device of claim 1 , wherein said matching network includes at least one adjustable capacitance that is adjusted by said tune signal.

3. The wireless device of claim 1 , wherein said detector further comprises a power detector that provides a power value indicative of a power level of said reflected electrical signal, and wherein said controller repeatedly adjusts said tune signal and monitors said power value to reduce said power value.

4. The wireless device of claim 3 , wherein said controller repeatedly adjusts said tune signal and monitors said power value until said power value is no greater than a threshold power value.

5. The wireless device of claim 3 , wherein said controller repeatedly adjusts said tune signal by an incremental amount.

6. The wireless device of claim 3 , wherein said controller repeatedly adjusts said tune signal according to a binary search method.

7. The wireless device of claim 1 , wherein said controller uses said demodulated information to determine a value of said tune signal that achieves an optimal transfer function of said matching network.

8. The wireless device of claim 1 , wherein said controller uses said demodulated information to calculate an input impedance of said matching network, to calculate an input impedance of said antenna based on said input impedance of said matching network and a transfer function of said matching network, to calculate an optimal output impedance of said matching network based on said input impedance of said antenna, to calculate an optimal transfer function of said matching network based on said optimal output impedance of said matching network, and to choose a value of said tune signal that adjusts said transfer function of said matching network that is sufficiently close to said optimal transfer function.

9. The wireless device of claim 8 , wherein said matching network is modified by a transfer function offset before said reflected electrical signal is demodulated into said demodulated information.

10. The wireless device of claim 1 , further comprising a transceiver that performs transmit and receive operations using said electrical communication path and said antenna, and wherein said transceiver comprises a Z-wave transceiver that performs said transmit and receive operations according to a Z-wave wireless communications protocol.

11. A method of adaptively tuning an antenna of a wireless device, comprising:
detecting a reflected electrical signal on an electrical communication path from the antenna during transmission of a wireless signal;
demodulating the reflected electrical signal into demodulated information; and
adjusting, based on the demodulated information, a tune value to reduce the strength of the reflected electrical signal.

12. The method of claim 11 , wherein said adjusting comprises adjusting a transfer function of the matching network.

13. The method of claim 12 , wherein said adjusting comprises adjusting a capacitance of the matching network.

14. The method of claim 11 , further comprising:
said converting comprises converting the reflected electrical signal into a power value indicative of a power level of the reflected electrical signal; and
wherein said adjusting comprises repeatedly adjusting the tune value to reduce the power value.

15. The method of claim 14 , wherein said repeatedly adjusting comprises repeatedly adjusting the tune value until the power value is no greater than a threshold power value.

16. The method of claim 14 , wherein said repeatedly adjusting comprises repeatedly adjusting the tune value by an incremental amount.

17. The method of claim 14 , wherein said repeatedly adjusting comprises repeatedly adjusting the tune value according to a binary search method.

18. The method of claim 11 , wherein:
said converting comprises using the demodulated information to determine an optimal transfer function of the matching network; and
wherein said adjusting comprises adjusting the tune value to modify the transfer function of the matching network towards the optimal transfer function.

19. The method of claim 11 , further comprising:
using the demodulated information to calculate an input impedance of the matching network;
calculating an input impedance of the antenna based on the input impedance of the matching network and a transfer function of the matching network;
calculating an optimal output impedance of the matching network based on the input impedance of the antenna;
calculating an optimal transfer function of the matching network based on the optimal output impedance of the matching network; and
wherein said adjusting comprises adjusting the tune value to adjust a transfer function of the matching network that is sufficiently close to the optimal transfer function.

20. The method of claim 19 , prior to said demodulating the reflected electrical signal, further comprising modifying the matching network by a transfer function offset.

Assignees

• Silicon Lab Inc

Inventors

• Paulsen Olfert Paul
• Buskgaard Emil Feldborg
• Hansen Michael

Classifications

• H04B1/18

  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 title

• H04B1/40

  Circuits · CPC title

• H01Q1/50 Primary

  Structural association of antennas with earthing switches, lead-in devices or lightning protectors · CPC title

• H03H7/40 Primary

  Automatic matching of load impedance to source impedance · CPC title

• H04B1/0458

  Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages (matching circuits in general H03H) · CPC title