Wireless power transfer system with automatic foreign object rejection

A wireless power transmitter comprising:

• a transmitter coil structure comprising
• a magnetic layer having a geometric center line, the magnetic layer being curved symmetrically about the geometric center line;
• a first coil coupled to a second coil, the first coil and the second coil wound in such a way that when a current flows in the first coil in a first spatial direction the current flows in the second coil in a second spatial direction,
• the first coil and the second coil disposed on the magnetic layer substantially symmetrically about the geometric center line of the magnetic layer;
• a power circuit configured to provide a time-varying current to the transmitter coil structure;
• and
• a housing including an outer surface having a convex shape,
• the transmitter coil structure being disposed underneath the outer surface of the housing.

A wireless power transmitter comprising:

• a transmitter coil structure comprising
• a magnetic layer having a geometric center line, the magnetic layer forming an angle at the geometric center line;
• a first coil coupled to a second coil, the first coil and second coil wound in such a way that when a current flows in the first coil in a first spatial direction the current flows in the second coil in a second spatial direction,
• the first coil and the second coil disposed on the magnetic layer substantially symmetrically about the geometric center line of the magnetic layer;
• and
• a housing including an outer surface having a convex shape,
• the transmitter coil structure being disposed underneath the outer surface of the housing.