Abstract: Systems, apparatus and methods for seamless metal back cover for combined wireless power transfer, cellular, WiFi, and GPS communications are provided. In one aspect, an apparatus for wirelessly coupling with other devices comprises a metallic cover comprising a first metallic portion separated by a first non-conductive portion from a second metallic portion of the metallic portion to define a first slot. The apparatus further comprises a conductor comprising a first end portion electrically coupled to the metallic cover at the first metallic portion and a second end portion crossing the first end portion and electrically coupled to the metallic cover at the second metallic portion. The metallic cover and the conductor form a coupler configured to wirelessly receive power sufficient to charge or power a load of the apparatus from a wireless power transmitter.

Abstract: Certain aspects of the present disclosure are generally directed to apparatus and techniques for wireless charging. One example apparatus generally includes a plurality of inductive elements and signal generation circuitry coupled to the plurality of inductive elements and configured to generate a plurality of signals, where at least two signals of the plurality of signals have different magnitudes. In certain aspects, the signal generation circuitry is configured to drive the plurality of inductive elements using the plurality of signals, where at least one first inductive element of the plurality of inductive elements is driven using at least one first signal of the plurality of signals having a first phase and at least one second inductive element of the plurality of inductive elements is driven using at least one second signal of the plurality of signals having a second phase different from the first phase.

Abstract: A wireless power transfer system may include a primary resonator and one or more secondary resonators. At least one of the secondary resonators lie in overlapping relation to the primary resonator. An electromagnetic (EM) field generated by the primary resonator can couple to the secondary resonators, thus inducing current flow in the secondary resonators. EM fields generated by the secondary resonators interact with the EM field from the primary resonator to produce a resultant EM field.

Abstract: Disclosed is a wireless power transfer apparatus that includes a case for an electronic device. The case may have an electrically conductive panel portion and side portions defined along sides of the panel portion. The case further have at least one opening formed one of the side portions. A coil configured to couple to an externally generated magnetic field may have first segments that span a width of the panel portion of the case and second segments arranged along the side portions of the case and exposed through the at least one opening.

Abstract: An aspect of this disclosure is an apparatus for transmitting power wirelessly. The apparatus comprises a detection circuit and a processor. The apparatus also includes a power amplifier driving an antenna circuit of flexible antenna(s) configured for wireless power transfer. The processor determines that at least one measured variable of the power amplifier falls outside of a corresponding threshold range, indicative of a deformation of a physical shape of one of the flexible antennas or indicative of misalignment of the flexible antennas from a power receiver. The processor further commands the power amplifier to transition to a first power mode from a second power mode based on the determination that at least one of the measured variables falls outside of the corresponding threshold range. The antenna circuit in the first power mode transmits power at a power level less than the power level in the second power mode.

Abstract: Systems and methods for wirelessly transferring power via magnetic field in a wireless power transfer system. A plurality of coils are placed at different locations around a body and configured to generate respective magnetic fields over different portions of the body to charge a chargeable device implanted within the body. A time division scheme is used such that no portion of the body experiences an average SAR over time that exceeds a designated SAR limit.

Abstract: A wireless charging device includes: a base configured to be worn by a user; and a coil attached to the base and comprising an electrically conductive material shaped to produce a magnetic field to convey power wirelessly to a receiver in response to receiving power, the coil including multiple turns each having a turn length with at least one of the multiple turns having an adjustable turn length, the multiple turns being disposed along a common axis such that each of the multiple turns is disposed around the axis for the respective turn length of the turn.

Abstract: Disclosed are methods, devices, apparatuses, and systems for ultrasonic fingerprint sensing with an acoustic shielding structure. One or more layers in an ultrasonic fingerprint sensing system may reflect back ultrasonic waves due to acoustic impedance mismatch that can distort a fingerprint image. An acoustic shielding structure may be configured to absorb, store, trap, or otherwise attenuate ultrasonic waves. The acoustic shielding structure may be positioned underlying an ultrasonic sensor layer. In some implementations, the acoustic shielding structure may include a plurality of periodically spaced apart geometric features or holes in a medium.

Abstract: An apparatus for wireless power transfer includes a transmit antenna configured to generate a wireless field to power or charge a load, a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit antenna located outside of a periphery of the wireless charging area, and at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field such that the wireless field in the wireless charging area is stronger than the wireless field where the at least one shielding element overlaps the transmit antenna.

Abstract: A wireless-power coupling system includes: a first power coupler comprising a first coil, the first coil comprising a first electrically-conductive loop; a second power coupler comprising a second coil, the second coil comprising a second electrically-conductive loop; and a third power coupler comprising a third coil, the third coil comprising a third electrically-conductive loop; where the first electrically-conductive loop and the second electrically-conductive loop are non-parallel relative to each other and overlap each other at a first plurality of locations of the first electrically-conductive loop; and where the first electrically-conductive loop and the third electrically-conductive loop are non-parallel relative to each other and overlap each other at a second plurality of locations of the first electrically-conductive loop, the first plurality of locations being distinct from the second plurality of locations.

Abstract: This invention describes a method and apparatus for providing wireless power. The methods and systems disclosed consist of a first coil having at least one loop forming an inner area inside boundaries of the at least one loop and an outer area outside the boundaries of the at least one loop, the first coil configured to generate a first alternating magnetic field for charging or powering a wireless power device, the first alternating magnetic field having a first magnetic field component with a first phase in the inner area, the first alternating magnetic field also having a second magnetic field component with a second phase in the outer area, and the second phase different from the first phase. In some aspects, the methods and systems comprise a second coil comprising a portion within the outer area, the second coil configured to reduce a magnitude of the second magnetic field component.

Abstract: Systems, methods and apparatus are disclosed for a dual mode wireless power receiver. In accordance with on aspect, an apparatus for receiving wireless power is provided. The apparatus includes a first coil configured to wirelessly receive power from a first transmitter configured to generate a first alternating magnetic field having a first frequency. The apparatus further includes a second coil configured to wirelessly receive power from a second transmitter configured to generate a second alternating magnetic field having a second frequency higher than the first frequency. The second coil is positioned to enclose the first coil. A first coupling factor between the first coil and a coil of the first transmitter is higher than a second coupling factor between the second coil and a coil of the second transmitter when the first and second coils are positioned within respective charging regions of the first and second transmitters.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus for controlling a power level of wireless power transfer. Certain aspects provide a wireless power receiver. The wireless power receiver includes an antenna and a rectifier. The rectifier includes a first diode and a second diode. The wireless power receiver further includes a resistor in parallel with the first diode. A first terminal of the resistor is coupled to a first terminal of the first diode. A second terminal of the resistor is coupled to a second terminal of the first diode.

Abstract: An aspect of this disclosure is an apparatus for receiving power wirelessly. The apparatus may be characterized by an impedance comprising a resistive component and a reactance component. The apparatus comprises an antenna circuit configured to receive power from a wireless charging field generated by a power transmitter, and to communicate with the power transmitter via a reflected signal, the reflected signal having a fundamental frequency. The apparatus may further comprise a control circuit coupled to the antenna circuit to generate the reflected signal. The reflected signal may be generated by performing at least one of: varying the resistive component of the impedance to generate a signal in the reflected signal having a frequency less than the fundamental frequency; and varying the reactance component of the impedance to change a phase of the reflected signal.

Abstract: Disclosed is a wireless charging system for a wearable device having a plurality of coils configured to couple to an externally generated magnetic field and provide power to an electronic component in the wearable device. The coils may include a first coil integrated with a device body of the wearable device and a second coil disposed in a portion of the wearable device that is configured to secure the wearable device to a user. The second coil may have a non-planar contour.

Abstract: A method and system for providing wireless power transfer through a metal object by forming a loop conductor from the metal object through a feature or component embedded within the metal object and by replacing portions of the metal object with insulating components. The method and system utilize a recessed channel to install and isolate conductors that are connected to transmitter or receiver circuits and enable wireless power transfer and other communications. The recessed channel creates a loop around at least a portion of the metal object such that the conductor installed therein may form a loop conductor, which may be connected to a source or sink. In some implementations, a logo embedded within the metal object may create a loop formed by the metal object with a current path around the logo, wherein the metal object itself may be configured to operate as the conductor.

Abstract: An apparatus for wireless power transfer includes a transmit antenna configured to generate a wireless field to power or charge a load, a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit antenna located outside of a periphery of the wireless charging area, and at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field such that the wireless field in the wireless charging area is stronger than the wireless field where the at least one shielding element overlaps the transmit antenna.

Abstract: Exemplary embodiments of the present disclosure are related to a wireless power resonator and method that includes a wireless power transmit element. The wireless power transmit element may include a substantially planar transmit antenna configured to generate a magnetic field and formed from a conductive trace including a plurality of distributed inductive elements along the conductive trace. The transmit element may further include a filter formed from selected ones of the plurality of distributed inductive elements of the planar transmit antenna and configured to generate at least one frequency response.

Abstract: A uniform magnetic field may provide better performance in wireless power transmitters due to smaller impedance variations in an output of a power amplifier of a wireless power transmitter and also allow for wireless power transmitter pads to be thinner. One aspect of the disclosure provides a device for wireless power transfer. The device comprises a substantially planar transmit antenna that is configured to generate a magnetic field. The device also comprises a pad having a charging surface. At least a portion of the transmit antenna is disposed in the pad. The device also comprises a ferromagnetic material having a shape and a position relative to the transmit antenna. At least one of the shape or position of the ferromagnetic material, or a combination thereof, is selected to modify a distribution of the magnetic field at the charging surface.

Abstract: This disclosure provides methods and apparatus for wirelessly transferring power. A first aspect of this disclosure is an apparatus for receiving power wirelessly. The apparatus comprises a receive circuit configured to receive wireless communication and charging power. The apparatus also comprises a metallic structure defining a gap extending from a first surface to a second surface, and through the metallic structure, the first surface opposite the second surface. The metallic structure is configured to receive the charging power from a wireless charging field oscillating at a first frequency. The metallic structure is further configured to convey the received power to the receive circuit via first and second connecting feeds. The metallic structure is also further configured to shield the receive circuit from interference at frequencies other than the first frequency.