A coil arrangement with reduced core losses is provided. The coil arrangement has a first coil and a second coil and a ferrite layer below the coils. A perpendicular recess in the ferrite layer is provided to reduce magnetic flux density in a center conduction path.

A resonant induction wireless power transfer coil assembly designed for low loss includes a wireless power transfer coil, a non-saturated backing core layer adjacent the wireless power transfer coil, an eddy current shield, a gap layer between the backing core layer and the eddy current shield, and an enclosure that encloses the wireless power transfer coil, backing core layer, gap layer and eddy current shield. The gap layer has a thickness in a thickness range for a given thickness of the backing core layer where eddy current loss in the eddy current shield is substantially flat over the thickness range. A thickness of the backing core layer and a thickness of the gap layer are selected where a total power loss comprising power loss in the backing core layer plus eddy current loss over the gap layer is substantially minimized.

A magnetic conductive substrate is provided and is used for wireless charging or wireless communication. The magnetic conductive substrate includes a first magnetic conductive layer, a second magnetic conductive layer, and a third magnetic conductive layer. The first magnetic conductive layer has a first magnetic permeability, the second magnetic conductive layer has a second magnetic permeability, and the third magnetic conductive layer has a third magnetic permeability. The second magnetic conductive layer is disposed between the first magnetic conductive layer and the third magnetic conductive layer, the first magnetic permeability is different from the second magnetic permeability, and the second magnetic permeability is different from the third magnetic permeability.

A choke is used to carry out high-voltage tests. The choke includes: a housing; a coil arranged in an interior of the housing; at least one electrically conductive component arranged between the coil and the housing; and a flux guide configured to guide a magnetic flux that is configured to be generated by the coil. The flux guide includes a ferromagnetic material; and is arranged between the coil and the at least one electrically conductive component in such a way that the magnetic flux that is configured to be generated by the coil is guided past the electrically conductive component.

A method for producing an inductive charging device may include inserting a ferrite and a coil, wound from a braid, into a mould; and encasing the ferrite and the braid at least partially with a plastic in a low pressure casting method, a pressing transfer moulding method, or an injection moulding method.

An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may have coplanar power transmitting and power receiving coils. The transmitting coil may be positioned within a central opening of the receiving coil. The removable accessory may have an embedded receiving coil configured to receive wireless power from the transmitting coil of the electronic device. The receiving coil of the electronic device may receive wireless power from a power transmitting device such as charging mat. The receiving coil of the electronic device may operate up to a higher maximum power than the transmitting coil of the electronic device. The power transmitting coil and power receiving coil in the electronic device may operate at different power transmission frequencies. To mitigate crosstalk, the power transmitting coil's operation frequency may be a non-integer multiple of the power receiving coil's operation frequency.

A device for high-frequency communication and for the inductive charging of an apparatus, including a charging surface, at least one charging antenna emitting a magnetic field at a low frequency and a layer of ferromagnetic material. The device includes at least one communication antenna and a printed circuit board. The communication antenna is in the form of a coil locally surrounding the layer with an axis of symmetry located in a plane parallel to the layer. The material of the layer is selected so as to have, at high frequency, an imaginary part with sufficiently high permeability to generate leaks on a surface of the layer extending perpendicular to the layer, while at the same time maintaining, at low frequency, an imaginary part with sufficiently low permeability to allow inductive charging.

An antenna module according to one embodiment of the present invention, comprises: a coil layer including a wound first coil; a shield layer disposed on the coil layer and including a plurality of sequentially stacked magnetic sheets; and a protection layer disposed on the shield layer, wherein the thickness of an edge of the shield layer is greater than the thickness of the center of the shield layer, and the total separation distance between the plurality of magnetic sheets at the edge of the shield layer is greater than the total separation distance between the plurality of magnetic sheets at the center of the shield layer.

A power receiving device is disposed underwater. The power receiving device includes a housing formed of a weak magnetic material, a ferromagnetic body that surrounds an outer side of the housing and is formed of a ferromagnetic material, and a power receiving coil wound around an outer side of the ferromagnetic body.

Provided is an antenna structure configured to wirelessly charge, the antenna structure including an insulating substrate, a coil formed on a first surface of the insulating substrate in a winding structure, the coil being wound a certain number of times in a clockwise and/or a counterclockwise direction around an axis normal to the insulating substrate, a coating layer including a first magnetic material, the coating layer being disposed adjacent to and surrounding the coil in a winding structure corresponding to the winding structure of the coil, and a shielding sheet including a second magnetic material and facing the second surface of the insulating substrate.