Integrated resonator-shield structures
Described herein are configurations for an integrated resonator-shield structure for wireless power transfer. In embodiments a conductor shield is used to shield the resonator from perturbing objects. In embodiments the conductor shield is used for a current return path for the conductors of the resonator. The resonator shield can be divided into separate conductor segments to tailor the current distributions in the conductor shield.
1. A resonator, comprising:
a member formed of a magnetic material and comprising a first surface, a second surface opposite the first surface, a third surface, and a fourth surface opposite the third surface; and
a resonator coil comprising:
a first plurality of loops, wherein each loop in the first plurality comprises a first portion adjacent to the first surface that extends in a first plane, and a second portion that extends around the third surface in a second plane that is not coplanar with the first plane; and
a second plurality of loops, wherein each loop in the second plurality comprises a first portion adjacent to the first surface that extends in a third plane, and a second portion that extends around the fourth surface in a fourth plane,
wherein the first plurality of loops defines a first winding direction relative to an axis extending perpendicular to the first plane, and the second plurality of loops defines a second winding direction different from the first winding direction relative to the axis; and
wherein the first winding direction is clockwise relative to the axis, and the second direction is counterclockwise relative to the axis.
2. The resonator of claim 1 , wherein the first and second pluralities of loops are symmetric with respect to a point in the first plane.
3. The resonator of claim 1 , wherein the first and second pluralities of loops are positioned with respect to the member so that when an alternating current flows through the resonator coil, the resonator coil generates a magnetic field with a dipole moment that extends in a direction parallel to the first surface.
4. The resonator of claim 1 , wherein the second plane is coplanar with the second surface.
5. The resonator of claim 1 , wherein the fourth plane is coplanar with the second surface.
6. The resonator of claim 1 , wherein one member of the first plurality of loops is connected to one member of the second plurality of loops.
7. The resonator of claim 1 , further comprising at least one capacitor coupled to the resonator coil.
8. The resonator of claim 1 , wherein the first and third planes are not coplanar.
9. The resonator of claim 1 , wherein the first and third planes are coplanar.
10. The resonator of claim 9 , wherein the first and third planes are parallel to the first surface.
11. The resonator of claim 1 , wherein the second and fourth planes are not coplanar.
12. The resonator of claim 1 , wherein the second and fourth planes are coplanar.
13. The resonator of claim 12 , wherein the second and fourth planes are parallel to the first plane.
14. The resonator of claim 1 , wherein at least a portion of the resonator coil is formed by conductive traces on a printed circuit board.
15. The resonator of claim 1 , wherein the resonator coil is formed of Litz wire.