Abstract: An electronic device can include a metallic housing defining an interior that contains one or more systems of the electronic device. The metallic housing can further define a pocket within the metallic housing separated from the interior. The pocket can have a window to an exterior of the metallic housing to facilitate wireless power transfer. An electronic device can include a non-metallic housing defining an interior that contains one or more systems of the electronic device and a wireless power transfer module that further includes a metallic structure defining a receptacle separated from the interior housing. The receptacle can have at least one open side to facilitate wireless power transfer. In either case, the wireless power transfer coil can be disposed at least partially or completely within the pocket or receptacle.

Abstract: A device in a wireless power system may be operable with a removable accessory such as a case. The device may transmit or receive wireless power through the case while the electronic device is coupled to the case. The case may have a folio shape with a front cover portion that covers the display of the electronic device. The case may have an embedded ferrimagnetic core that relays magnetic flux during wireless power transfer operations. Magnetic alignment structures in the case may position the ferrimagnetic core in the case in a high magnetic flux density region between the power transmitting device and the power receiving device. The ferrimagnetic core relays the magnetic flux between a transmitting coil in the power transmitting device and a receiving coil in the power receiving device. The ferrimagnetic core may be formed in a front portion, a sidewall, or a rear wall of a case.

Abstract: A method of modeling a wireless power transfer system can include constructing a loss-split circuit model of the wireless power transfer system. The loss-split circuit model can include a plurality of resistance values corresponding to power losses in selected components of the power system. The method can further include performing a plurality of finite element analyses to determine the plurality of resistor values. The one or more resistance values can correspond to power losses associated with one or more of: a transmitter coil, a receiver coil, friendly metal associated with a transmitter, friendly metal associated with a receiver, and a foreign object.

Abstract: A wireless power transfer system can include an electronic device including a first wireless power transfer coil and wireless power transfer circuitry coupled to the wireless power transfer coil. The wireless power transfer circuitry can be capable of receiving power and transmitting power wirelessly via the first wireless power transfer coil. The system can further include an accessory device including a second wireless power transfer coil, a rectifier coupled to the second wireless power transfer coil, and an energy storage device coupled to the rectifier by a regulator circuit. The wireless power transfer circuitry can operate in a pulsed or burst wireless power transfer mode to deliver power to the accessory device.

Abstract: An electronic device (that is capable of both transmitting and receiving wireless power) may be physically and inductively coupled to a removable accessory (that only receives wireless power). The electronic device and removable accessory may optionally be placed on a power transmitting device. In response to the electronic device and removable accessory being placed on a wireless power transmitting device, the electronic device may switch from a power transmitting mode (in which the electronic device transmits wireless power to the removable accessory) to a power receiving mode (in which the electronic device receives wireless power from the wireless power transmitting device). To ensure the electronic device detects the wireless power transmitting device and switches to the power receiving mode in this scenario, the electronic device may transmit wireless power in bursts separated by sleep periods while in the power transmitting mode.

Abstract: A wireless power system has electronic devices that mate with each other to transfer wireless power. Each device may have a wireless power coil. Alignment magnets may be used to magnetically attach devices to each other so that the coils in the devices are aligned with respect to each other for wireless power transfer. The system may include first, second, and third devices. The first and third devices may have fixed alignment magnets with poles of opposite magnetic polarity that allow the first and third devices to be attached to each other so that their coils are aligned. The second device may have a reconfigurable alignment magnet that is operable in a first mode in which the second device is magnetically attached to the first device and a second mode in which the second device is magnetically attached to the third device.

Abstract: The disclosure is directed to wireless power systems that include a ferromagnetic core formed of nanocrystalline material disposed on a ferrite. The wireless power systems can have reduced saturation and/or lossiness.

Abstract: An accessory for improving wireless power transfer efficiency in a wireless power transfer system can include a magnetic (e.g., ferrite) core dimensioned and positioned so as to reduce flux coupling from the PTx winding into friendly metal of the PRx and/or to enhance flux coupling from the PTx winding to the PRx winding. The core may define an aperture corresponding to an outer dimension (e.g., outer diameter) of the PRx winding. The core may further have an outer dimension selected to intercept sufficient flux to reduce flux coupling into the friendly metal of the PRx, such as an outer dimension corresponding to an outer dimension (e.g., outer diameter) of the PTx winding. The accessory may be a case for the PRx device or may be configured to be affixed to the face of the PTx device and may also include one or more alignment fixtures.

Abstract: An electronic device in a wireless power system may be operable with a removable accessory such as a case. The device may convey wireless power to, from, or through the case while the device is coupled to the case. The device may have coplanar power transmitting and power receiving coils. The removable accessory may have an embedded switchable ferrimagnetic core and a coil that overlaps the switchable ferrimagnetic core. The switchable ferrimagnetic core may be operable in a first state where the switchable ferrimagnetic core is unsaturated. The switchable ferrimagnetic core may be operable in a second state where the switchable ferrimagnetic core is saturated by a magnetic field from a permanent magnet in a wireless power transmitting device. In the second state, the switchable ferrimagnetic core may have a lower magnetic permeability and higher magnetic reluctance than in the first state.

Abstract: A device in a wireless power system may be operable with a removable accessory such as a case. The device may transmit or receive wireless power through the case while the electronic device is coupled to the case. The case may have a folio shape with a front cover portion that covers the display of the electronic device. The case may have an embedded ferrimagnetic core that relays magnetic flux during wireless power transfer operations. Magnetic alignment structures in the case may position the ferrimagnetic core in the case in a high magnetic flux density region between the power transmitting device and the power receiving device. The ferrimagnetic core relays the magnetic flux between a transmitting coil in the power transmitting device and a receiving coil in the power receiving device. The ferrimagnetic core may be formed in a front portion, a sidewall, or a rear wall of a case.

Abstract: One embodiment provides an apparatus for wireless power transmission, comprising: a resonator comprising: a three dimensional structure; and an energy storage mechanism operatively coupled to the three dimensional structure; wherein the three dimensional structure and energy storage mechanism produce standing electromagnetic waves upon driving the resonator. Other systems, methods, apparatuses, and products are described and claimed.

Abstract: An embodiment provides a method of wireless power transmission, including: powering a transmitter that produces electromagnetic waves in a three dimensional structure; selecting a transmission frequency that is a resonance frequency for the three dimensional structure; and transmitting, using the transmitter, electromagnetic waves within the three dimensional structure on the transmission frequency selected. Other systems, methods, apparatuses and products are described and claimed.

Abstract: One embodiment provides an apparatus for wireless power transmission, comprising: a resonator comprising: a three dimensional structure; and an energy storage mechanism operatively coupled to the three dimensional structure; wherein the three dimensional structure and energy storage mechanism produce standing electromagnetic waves upon driving the resonator. Other systems, methods, apparatuses, and products are described and claimed.

Abstract: An embodiment provides a method of wireless power transmission, including: powering a transmitter that produces electromagnetic waves in a three dimensional structure; selecting a transmission frequency that is a resonance frequency for the three dimensional structure; and transmitting, using the transmitter, electromagnetic waves within the three dimensional structure on the transmission frequency selected. Other systems, methods, apparatuses and products are described and claimed.

Abstract: An optical device includes a near field transducer; and a dielectric resonant structure coupled to the near field transducer; wherein the dielectric resonant structure comprises a dielectric material that decreases a dissipation of energy in the dielectric resonant structure, relative to other dissipations of energy associated with other materials; and wherein the decrease in the dissipation of energy increases an efficiency of energy transfer from the near field transducer to a target structure, relative to other efficiencies of energy transfer from the near field transducer to the target structure.

Abstract: An optical device includes a near field transducer; and a dielectric resonant structure coupled to the near field transducer; wherein the dielectric resonant structure comprises a dielectric material that decreases a dissipation of energy in the dielectric resonant structure, relative to other dissipations of energy associated with other materials; and wherein the decrease in the dissipation of energy increases an efficiency of energy transfer from the near field transducer to a target structure, relative to other efficiencies of energy transfer from the near field transducer to the target structure.