Adaptive antenna matching

1. A portable communication device comprising:

an antenna;

a radio circuit to send a radio frequency signal to the antenna via a signal path;

a first matching network including a number of network components and configured to be in the signal path;

a detector configured to detect an electromagnetic field from the antenna; and

a control unit configured to control matching of the antenna by influencing at least one of the first matching network or the antenna based on the detected electromagnetic field, where when controlling the matching, the control unit is to:

compare data indicative of the detected electromagnetic field to a set of pre-stored reference data indicative of fields relating to a number of known parameters associated with different conditions of antenna use,

select a matching strategy associated with a portion of the pre-stored reference data based on the data indicative of the detected electromagnetic field, and

control the matching of the antenna based on the selected strategy.

2. The portable communication device of claim 1 , wherein when influencing the first matching network the control unit is configured to connect one or more of the network components into the signal path.

3. The portable communication device of claim 1 , wherein at least one of the network components is variable, and when influencing the first matching network the control unit is configured to change a magnitude of the at least variable component.

4. The portable communication device of claim 1 , further comprising:

a second matching network, wherein when controlling the matching the control unit is configured to switch from the first matching network to the second matching network in the signal path.

5. The portable communication device of claim 1 , wherein the first matching network includes a strip line, and when influencing the first matching network the control unit is configured to change a phase of a radio frequency signal by influencing the strip line.

6. The portable communication device of claim 5 , wherein when influencing the strip line the control unit is configured to connect the strip line into the signal path.

7. The portable communication device of claim 5 , wherein the strip line is disposed in the signal path, and when influencing the strip line the control unit is configured to change a length of the strip line.

8. The portable communication device of claim 1 , wherein the different conditions of antenna use include at least one of fingers of a user contacting the antenna, a head of the user contacting the portable communication device, the portable communication device being disposed in clothing of the user, the portable communication device being disposed on a surface, or the portable communication device being disposed in free space.

9. The portable communication device of claim 1 , wherein the portable communication device is a cellular phone.

10. In a portable communication device, a method comprising:

detecting a electromagnetic field associated with an antenna configured to receive a radio frequency signal from a radio circuit, wherein a first matching network that includes a number of network components is configured to be operably disposed in a signal path between the antenna and the radio circuit; and

controlling a matching of the antenna by influencing at least one of the first matching network or the antenna based on the detected electromagnetic field, where the controlling the matching comprises:

comparing data indicative of the detected electromagnetic field to a set of pre-stored reference data indicative of fields relating to a number of known parameters associated with different conditions of antenna use,

selecting a matching strategy associated with a portion of the pre-stored reference data based on the data indicative of the detected electromagnetic field, and

controlling the matching of the antenna based on the selected strategy.

11. The method of claim 10 , wherein the influencing of the first matching network comprises connecting one or more components into the signal path.

12. The method of claim 10 , wherein at least one of the network components is variable, and the influencing the first matching network comprises changing a magnitude of the at least one variable network component.

13. The method of claim 10 , wherein the controlling the matching comprises switching, from the first matching network, a second matching network into the signal path.

14. The method of claim 10 , wherein the first matching network includes a strip line, and the influencing the first matching network comprises changing a phase of a radio frequency signal by influencing the strip line.

15. The method of claim 14 , wherein the influencing the strip line comprises connecting the strip line into the signal path between the radio circuit and the antenna.

16. The method of claim 14 , wherein the strip line is disposed in the signal path, and the influencing the strip line comprises changing a length of the strip line.

17. The method of claim 10 , wherein the different conditions of antenna use include at least one of fingers of a user contacting the antenna, a head of the user contacting the portable communication device, the portable communication device being disposed in clothing of the user, the portable communication device being disposed on a surface, or the portable communication device being disposed in free space.