Multiple-orientation wireless charging

1. A system comprising:

power signal (PS) circuitry configured to wirelessly transfer energy to a charging device; and

an antenna comprising a plane of traces, the antenna configured to, when driven by the PS circuitry:

generate a first magnetic field component parallel to the plane of traces; and

generate a second magnetic field component parallel to the plane of traces, the second magnetic field component oriented in a direction different from a direction of the first magnetic field component, and the first magnetic field component stronger than the second magnetic field component.

2. The system of claim 1 , wherein the first magnetic field component is oriented normal to an antenna plane of the charging device.

3. The system of claim 2 , wherein the antenna plane of the charging device is oriented orthogonally to the plane of traces.

4. The system of claim 1 , wherein the PS circuitry comprises a transceiver configured to establish a data communication link with the charging device.

5. The system of claim 4 , wherein the transceiver is configured to receive a status message comprising a field coupling indicator for the charging device over the data communication link.

6. The system of claim 5 , wherein the PS circuitry is configured to adjust a ratio of the first magnetic field component and second magnetic field component to adjust the field coupling responsive to the status message.

7. The system of claim 1 , wherein the PS circuitry is configured to determine a field coupling for the charging device by measuring a load of the antenna.

8. The system of claim 1 , wherein:

the antenna is configured to generate a third magnetic field component normal to the plane of traces when an antenna plane of the charging device is oriented parallel to the plane of traces.

9. The system of claim 1 , wherein the traces comprise:

first parallel traces aligned along a first direction, the first parallel traces configured to, when driven by the PS circuitry, generate the first magnetic field component; and

second parallel traces aligned along a second direction, the second parallel traces configured to, when driven by the PS circuitry, generate the second magnetic field component, the second direction different from the first direction.

10. The system of claim 9 , wherein the first direction is orthogonal to the second direction.

11. The system of claim 9 , wherein the first parallel traces are interconnected via first return lines, a length of the first return lines configured to enforce a phase relationship among the first parallel traces, when the first parallel traces are driven by the CS circuitry.

12. The system of claim 11 , wherein the return lines are separated from the first parallel traces by a magnetic shielding layer.

13. The system of claim 1 , further comprising a magnetic shield, the magnetic shield configured to:

cover a first portion of the plane of traces; and

expose a second portion of the plane of traces.

14. The system of claim 1 , wherein:

the plane of traces comprises multiple macroblocks; and

the PS circuitry is configured to:

activate a first macroblock; and

forgo activation of a second macroblock when the first macroblock is coupled to an antenna of the charging device more strongly than the second macroblock.

15. A method comprising:

coupling energy wirelessly from a charging station (CS) to a charging device by:

driving a first trace of a CS antenna to generate a first field component of a magnetic field and a second field component of the magnetic field, the first field component and the second field component parallel to the CS antenna; and

driving a second trace of the CS antenna to adjust a signal ratio between the first field component and the second field component to control coupling between the magnetic field and a charging device antenna.

16. The method of claim 15 , wherein driving the second trace of the CS antenna to adjust the signal ratio between the first field component and the second field component comprises:

receiving feedback from the charging device, the feedback indicating the coupling between the charging device antenna and the magnetic field; and

responsive to the feedback, changing a driving current of the first trace, the second trace, or both.

17. The method of claim 16 , wherein receiving feedback comprises receiving coupling data over a communication link between the charging device and the CS, a reflected load of the charging device antenna, or both.

18. A system comprising:

an antenna configured to couple energy wirelessly to a charging device, the antenna comprising:

a first trace configured to, when driven:

emit a first magnetic field component along a first direction; and

emit a second magnetic field component along a second direction, the second direction orthogonal to the first direction; and

a second trace configured to, when driven, emit a third magnetic field component that cancels a portion of the second magnetic field component to align a total magnetic field along the first direction; and

power signal (PS) circuitry coupled to the antenna, the PS circuitry configured to drive the antenna to wirelessly charge the charging device.

19. The system of claim 18 , wherein:

the first and second traces are aligned parallel to one another;

the first direction is orthogonal to the first and second traces; and

the second direction is parallel to the first and second traces.

20. The system of claim 18 , further comprising:

a return trace coupled to the first and second traces, the return trace configured to pass a driving signal from the first trace to the second trace; and

a magnetic shield configured to separate the first and second traces from the return trace.