A wireless power transmitter includes a power transmit coil configured to generate a magnetic field for wirelessly coupling charging power to one or more receiver devices, the magnetic field having a magnetic field distribution over an area defining a charging region, a circuit configured to alter the magnetic field generated by the power transmit coil to alter the magnetic field distribution, and a controller operably coupled to the circuit, the controller configured to control the circuit to alter the magnetic field distribution responsive to a detected characteristic of the one or more receiver devices.