Shield for a wireless power transmitter
Techniques for focusing an energy radiated by a wireless power transmitting unit are described. An example power transmitting unit includes a transmit coil configured to generate a magnetic field to wirelessly power a device within an active wireless charging area. The power transmitting unit also includes a power generating circuitry to deliver a current to the transmit coil to generate the magnetic field. The power transmitting unit also includes a patch array disposed in parallel with the transmit coil to reduce a strength of the magnetic field at frequencies outside of the operating frequency during operation of the power transmitting unit.
1. A power transmitting unit, comprising:
a transmit coil configured to generate a magnetic field to wirelessly power a device within an active wireless charging area;
a power generating circuitry to deliver a current to the transmit coil to generate the magnetic field at an operating frequency; and
a patch array disposed in parallel with the transmit coil to reduce a strength of the magnetic field at frequencies outside of the operating frequency during operation of the power transmitting unit;
wherein the patch array comprises an array of conductive patches coupled to a ground plane disposed in parallel with the array of conductive patches;
wherein the array of conductive patches are separated from the ground plane by an insulating material and conductively coupled to the ground plane by a via through the insulating material; and
wherein the array of conductive patches comprise an outer patch separated from the via by a gap, wherein the outer patch is conductively coupled to the via through an LC circuit.
2. The power transmitting unit of claim 1 , wherein the array of conductive patches is disposed below the transmit coil.
3. The power transmitting unit of claim 1 , wherein each conductive patch of the array of conductive patches is coupled to an adjacent conductive patch of the patch array through a resonant circuit.
4. The power transmitting unit of claim 1 , wherein the LC circuit comprising a capacitor and an inductor connected in parallel.
5. The power transmitting unit of claim 1 , wherein the power transmitting unit is built into a table top.
6. A method of manufacturing a power transmitting unit, the method comprising:
forming a transmit coil configured to generate a magnetic field to wirelessly power a device within an active wireless charging area;
conductively coupling a power generating circuitry to the transmit coil, the power generating circuitry to deliver a current to the transmit coil to generate the magnetic field at an operating frequency; and
disposing a patch array in parallel with the transmit coil to reduce a strength of the magnetic field at frequencies outside of the operating frequency during operation of the power transmitting unit;
wherein the patch array comprises an array of conductive patches coupled to a ground plane disposed in parallel with the array of conductive patches;
wherein the patch array comprises an array of conductive patches coupled to a ground plane disposed in parallel with the array of conductive patches; and
wherein the array of conductive patches are separated from the ground plane by an insulating material and conductively coupled to the ground plane by a via through the insulating material.
7. The method of claim 6 , wherein the array of conductive patches is disposed below the transmit coil.
8. The method of claim 6 , wherein each conductive patch of the array of conductive patches is coupled to an adjacent conductive patch of the patch array through a resonant circuit.
9. The method of claim 6 , wherein the LC circuit comprising a capacitor and an inductor connected in parallel.
10. The method of claim 6 , comprising disposing the power transmitting unit into a table top.
11. A wireless charger, comprising:
a transmit coil configured to generate a magnetic field to wirelessly power a device within an active wireless charging area;
a power generating circuitry to deliver a current to the transmit coil to generate the magnetic field at an operating frequency; and
a patch array disposed in parallel with the transmit coil to reduce a strength of the magnetic field at frequencies outside of the operating frequency during operation of the wireless charger;
wherein the patch array comprises an array of conductive patches coupled to a ground plane disposed in parallel with the array of conductive patches;
wherein the array of conductive patches are separated from the ground plane by an insulating material and conductively coupled to the ground plane by a via through the insulating material; and
wherein the array of conductive patches comprise an outer patch separated from the via by a gap, wherein the outer patch is conductively coupled to the via through an LC circuit.
12. The wireless charger of claim 11 , wherein the array of conductive patches is disposed below the transmit coil.
13. The wireless charger of claim 11 , wherein each conductive patch of the array of conductive patches is coupled to an adjacent conductive patch of the patch array through a resonant circuit.
14. The wireless charger of claim 11 , wherein the LC circuit comprising a capacitor and an inductor connected in parallel.
15. The wireless charger of claim 11 , wherein the wireless charger is disposed within a table top.