A relay apparatus in a wireless power transmission system includes a relay power reception antenna that receives power transmission alternating current power from a power transmission power transmission antenna, a relay rectifier that converts the power transmission alternating current power into relay direct current power, a relay inverter circuit that converts the relay direct current power into relay alternating current power, and a relay power transmission antenna that wirelessly transmits the relay alternating current power. When transmitting data to the power transmission apparatus through amplitude modulation, the relay apparatus varies amplitude of voltage of the power transmission alternating current power received by the relay power reception antenna between a first amplitude and a second amplitude and performs control for eliminating a difference between a third amplitude of the relay alternating current power and a fourth amplitude of the relay alternating current power.

A wireless communication device has a display device and a transmitter that wirelessly transmits a wireless (e.g., NFC) signal from an antenna. The antenna is positioned such that the display device may be between the antenna and another wireless communication device that is to receive the signal, and the display device may attenuate such signal. A reflector of the display device is patterned with small gaps in order to limit the loop sizes of eddy currents that are induced by the wireless signal, thereby reducing parasitic power consumption of the reflector to the wireless signal. Thus, the presence of the gaps in the reflector improves the transparency of the display device to the wireless signal without significantly affecting the performance of the reflector in sinking heat and reflecting light.

One example discloses a near-field wireless device, including: a near-field antenna; a variable current source; a controller coupled to the near-field antenna and the variable current source; wherein the controller is configured to measure a transmit quality-factor (Qtx) of the near-field antenna; and wherein the controller is configured to increase current sent by the variable current source to the near-field antenna if the measured Qtx is lower than a minimum Qtx.

A wireless power transmitter includes a power conversion unit configured to transfer wireless power to a wireless power receiver by using magnetic coupling between the wireless power transmitter and the wireless power receiver; and a communication/control unit configured to control the wireless power and to perform transmission or reception of data based on communication with the wireless power receiver, wherein the communication/control unit receives from the wireless power receiver a received power packet (RPP) informing a value of power received by the wireless power receiver, transmits a bit pattern, in response to the RPP, requesting for transmitting at least one data packet from the wireless power transmitter to the wireless power receiver, receives a response packet from the wireless power receiver in response to the bit pattern, and transmits the at least one data packet to the wireless power receiver.

According to one aspect of the present disclosed subject matter, a receiver inductively powered by a transmitter for powering a load, the receiver comprising: a resonance circuit capable of tuning its resonance frequency for coupling with the transmitter and generate AC voltage; a power supply section configured to rectify the AC voltage and adjust a DC current and a DC voltage to the load; and a control and communication section designed to set parameters for the receiver and communicate operation points (OP) to the transmitter, wherein the parameters and the OP derived from determining a minimal power loss of the receiver.

A position-sensing sensor of a position-sensing system includes first and a second radio transponders that each have a transmitter/receiver connected to an antenna and has a memory for persistent data storage, wherein the first radio transponder has an energy supply source and is selectively switchable into a reduced energy consumption idle state and into an active operating state with complete range of functionality, where during the active operating state, a radio connection to a first radio transponder reader is established for position sensing, where the second radio transponder, which is inductively supplyable with energy by a radio transponder reader, upon entering a range of a second radio transponder reading unit, transfers the first radio transponder from the idle state into the active operating state or transfers position information associated with the second radio transponder to a server of the position-sensing system via the second radio transponder reader.

A system for detecting a specific relative position between a reader and a receiver, including: an inductive contactless receiver including an antenna winding and a circuit for selectively modulating a load; an inductive contactless reader including: a transceiver antenna circuit having nonzero mutual inductance with the antenna winding for the position, a communication circuit connected to the transceiver antenna circuit, a receiver antenna circuit having mutual inductance with the antenna winding that exhibits a minimum for the position, and a processing circuit for: identifying presence of a receiver by detecting nonzero mutual inductance between the transceiver antenna circuit and an antenna winding, and detecting a mutual inductance minimum between the receiver antenna circuit and an antenna winding.

Methods and apparatuses for performing wireless charging are disclosed. A method of controlling a wireless power receiver includes receiving, through a power receiving circuit, a first power from a wireless power transmitter when the wireless power receiver is powered off; driving a communication controller using the received first power; establishing, by the communication controller, a communication connection with the wireless power transmitter, using a first communication stack stored in a first memory, while receiving the first power; and performing, by the communication controller, communication with the wireless power transmitter.

One example device having a variable impedance matching network includes a flexible substrate configured to flex in at least an X dimension and a Y dimension, wherein the X and Y dimensions are orthogonal and coplanar with a surface of the flexible substrate; an antenna formed on the flexible substrate, the antenna deformable in at least one of the X or Y dimensions, wherein an inductance (L.sub.A) of the antenna varies based on a flexing of the flexible substrate in the at least one of the X or Y dimensions, an impedance matching network formed on the flexible substrate and coupled to the antenna, the impedance matching network deformable in the at least one of the X or Y dimensions, and wherein a capacitance (C.sub.M) or inductance (L.sub.M) of the impedance matching network is configured to vary (i) based on the flexing of the flexible substrate in the at least one of the X or Y dimensions and a separation between two portions of the impedance matching network, and (ii) in proportion to the varying of L.sub.A to maintain a substantially constant impedance of the combination of the impedance matching network and the antenna.

Aspects of the subject disclosure may include, for example, a coupling device includes a circuit that receives a signal. At least one passive electrical circuit element generates an electromagnetic field in response to the signal. A portion of the electromagnetic field is guided by a surface of a transmission medium to propagate as a guided electromagnetic wave longitudinally along the transmission medium. Other embodiments are disclosed.