Wireless power transfer using multiple coil arrays

A wireless power device comprising:

• a power source configured to generate a first time-varying current;
• a first coil configured to receive the first time-varying current from the power source, wherein the first time-varying current flows in the first coil in a first direction;
• a second coil coupled to the first coil in such a way that the first time-varying current flows in the second coil in a second direction, wherein the first direction is opposite from the second direction;
• a third coil configured to receive a second time-varying current, wherein the time varying current flows in the third coil in a third direction and the third direction is opposite from the second direction;
• a fourth coil coupled to the third coil in such a way that the second time-varying current flows in the fourth coil in a fourth direction, wherein the fourth direction is opposite from the third direction and the first direction;
• a substantially planar layer of magnetic material configured to magnetically couple the first coil and the second coil, and to magnetically couple the third coil and the fourth coil;
• and
• an air gap in the substantially planar layer of magnetic material, wherein the air gap magnetically isolates the first coil from the third coil and magnetically isolates the second coil from the fourth coil,
• wherein a central axis of each of the first coil, second coil, third coil, and fourth coil is normal to a surface of the substantially planar layer of magnetic material.

A wireless power device comprising:

• a first coil wound in a first direction such that the first coil is configured to generate a first magnetic field having a first polarity;
• a second coil coupled to the first coil, wherein the second coil is wound in a second direction and is configured to generate a second magnetic field having a second polarity, wherein the first polarity is opposite from the second polarity;
• and
• a substantially planar layer of magnetic material configured to magnetically couple the first coil with the second coil,
• wherein a central axis of the first coil is normal to a surface of the substantially planar layer of magnetic material and a central axis of the second coil is normal to the surface of the substantially planar layer of magnetic material.