An antenna configured for near field communication includes a first coil for transmitting and receiving signals having a first frequency and a second coil for transmitting and receiving signals having a second frequency greater than at least twice the first frequency. The first and second coils are magnetically coupled with a coupling coefficient greater than 0.5.

An antenna configured for near field communication includes a first coil for transmitting and receiving signals having a first frequency and a second coil for transmitting and receiving signals having a second frequency greater than at least twice the first frequency. The first and second coils are magnetically coupled with a coupling coefficient greater than 0.5.

A method of setting phases of a multitude of transmit elements of a phased array includes, in part, setting a phase of a first transmit element to N different values during each of N different time intervals, transmitting an electromagnetic signal from the first transmit element at each of the N time intervals, measuring a power of the electromagnetic signal at a receiving unit during each of the N time intervals, and selecting coefficients of a basis function such that a difference between a power value computed by the basis function and the measured power value associated with each of the N phases is smaller than a threshold value. The threshold value is optionally defined by a minimum of the sum of squares of the difference between a power value computed by the basis function and the power value for each of the N phases.

A method of setting phases of a multitude of transmit elements of a phased array includes, in part, setting a phase of a first transmit element to N different values during each of N different time intervals, transmitting an electromagnetic signal from the first transmit element at each of the N time intervals, measuring a power of the electromagnetic signal at a receiving unit during each of the N time intervals, and selecting coefficients of a basis function such that a difference between a power value computed by the basis function and the measured power value associated with each of the N phases is smaller than a threshold value. The threshold value is optionally defined by a minimum of the sum of squares of the difference between a power value computed by the basis function and the power value for each of the N phases.

Inductive wireless power transfer systems are provided for medical devices, such as implantable medical devices (IMDs). The systems may comprise a transmitter unit and a receiver unit and may be configured for transferring power and/or signals from the transmitter unit to the receiver unit and/or vice versa. The transmitter unit may comprise an energy source, a transmitter antenna, and a supply line connected in between the energy source and the antenna. The receiver unit may comprise a receiver antenna and a rectifier output. The transmitter antenna and the receiver antenna may be configured to provide a wireless power transfer link. The supply line may comprise a virtual resistance unit, which may be configured to provide a virtual resistance, which may be determined such that the rectifier output provides a substantially constant or less varying charge current over a predetermined distance range, for a large range of implant depths.

Inductive wireless power transfer systems are provided for medical devices, such as implantable medical devices (IMDs). The systems may comprise a transmitter unit and a receiver unit and may be configured for transferring power and/or signals from the transmitter unit to the receiver unit and/or vice versa. The transmitter unit may comprise an energy source, a transmitter antenna, and a supply line connected in between the energy source and the antenna. The receiver unit may comprise a receiver antenna and a rectifier output. The transmitter antenna and the receiver antenna may be configured to provide a wireless power transfer link. The supply line may comprise a virtual resistance unit, which may be configured to provide a virtual resistance, which may be determined such that the rectifier output provides a substantially constant or less varying charge current over a predetermined distance range, for a large range of implant depths.

A method performed by a first network node (111). The method is for handling charging of a wireless device (130). The first network node (111) and the wireless device (130) operate in a wireless communications network (100). The first network node (111) modulates (307) one or more beam forming beams (121) in an antenna array (124) controlled by the first network node (111) with a pulse width modulation. The first network node (111) then charges (308), wirelessly, the wireless device (130), with the modulated one or more beam forming beams (121).

The disclosed wireless transmitter estimates a client location in space and transmits power in the form of electromagnetic (EM) waves to that location. In response to receiving the power, a client sends a power request signal. In some implementations, the power request signal includes a request that the wireless transmitter transmit more power to the client. In response to the power request signal, the wireless transmitter can modify the power transmitted to the client to increase/decrease the amount of power the client is receiving. For example, the wireless transmitter can modify the emitted EM waves to increase coherent addition or decrease coherent addition at the location of the client to increase the amount of power the client receives. In some implementations, the wireless transmitter modifies the phase distribution of EM waves to increase the amount of power a client receives.

The disclosed wireless transmitter estimates a client location in space and transmits power in the form of electromagnetic (EM) waves to that location. In response to receiving the power, a client sends a power request signal. In some implementations, the power request signal includes a request that the wireless transmitter transmit more power to the client. In response to the power request signal, the wireless transmitter can modify the power transmitted to the client to increase/decrease the amount of power the client is receiving. For example, the wireless transmitter can modify the emitted EM waves to increase coherent addition or decrease coherent addition at the location of the client to increase the amount of power the client receives. In some implementations, the wireless transmitter modifies the phase distribution of EM waves to increase the amount of power a client receives.

An energy transfer system includes a spinal implant having an antenna, an antenna extender attached to a portion of the spinal implant in proximity to the antenna, and a reader device configured to send energy to the spinal implant via the antenna extender. The antenna extender extends away from the spinal implant. The spinal implant is configured to be positioned within a spinal area of a patient.