Wireless power transmitters and associated base stations for through-structure charging

A base station for a wireless power transfer system at an operating frequency, the base station comprising:

• an interface surface;
• a coil defining a top face and a bottom face, the coil configured to transmit a power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer;
• and
• a shielding comprising a magnetic backing and a magnetic wall, the magnetic wall and the magnetic backing defining a cavity that extends at least from the magnetic backing to the bottom face of the coil, the cavity configured to receive, at least in part, an object external to the base station, and
• wherein the bottom face of the coil is positioned above a top surface of the magnetic wall, such that the shielding is configured to concentrate magnetic fields created by the coil.

A power transmitter for wireless power transfer at an operating frequency, the power transmitter comprising:

• a coil defining a top face and a bottom face, the coil configured to transmit a power signal to a power receiver, the coil formed of wound Litz wire and including at least, a first layer and a second layer, each of the first layer and the second layer having a number of turns in a range of about 2 turns to about 5 turns;
• and
• a shielding comprising a magnetic backing and a magnetic wall, the magnetic wall and the magnetic backing defining a cavity that extends at least from the magnetic backing to the bottom face of the coil, the magnetic wall including a top surface, the magnetic backing defines a cutout, the cutout substantially centered concentric to one or more of the magnetic backing, the magnetic wall, the coil, and combinations thereof, and
• wherein the bottom face of the coil is positioned above the top surface of the magnetic wall, such that the shielding is configured to concentrate magnetic fields created by the coil.