An antenna unit includes: an external body; a display unit which is provided on one side of the external body and displays information; an antenna which is provided on the other side of the external body and is disposed to face the display unit at an interval therebetween; an internal body which accommodates the antenna and is movable with respect to the external body toward a side opposite to the display unit. The external body has a belt connecting section which protrudes toward the side opposite to the display unit. The internal body protrudes from the external body by moving toward the side opposite to the display unit. The internal body protrudes farther from the external body than the belt connecting section from the external body.

A contactless integrated circuit (IC) card reader configured to communicate with a contactless IC card includes an antenna circuit, a variable amplifier that amplifies a carrier signal at an amplification gain and outputs the amplified carrier signal to the antenna circuit as a transmit signal, a variable attenuator that attenuates a receive signal received through the antenna circuit at an attenuation ratio, and a controller that controls the amplification gain and the attenuation ratio based on the attenuated receive signal.

Example systems and methods are described that wirelessly charge a rechargeable battery associated with a lock. In one implementation, a rechargeable battery is electrically coupled to an electronic lock module associated with a door corresponding to a door frame. An electronic control module associated with the door frame and physically separate from the electronic lock module generates a wireless charging link between the electronic control module and the electronic lock module. The electronic control module transmits a charging signal to the electronic lock module via the wireless charging link, and the electronic lock module uses this charging signal to charge the rechargeable battery. The implementation also includes a lock associated with the door that can be locked or unlocked by the electronic lock module.

A power transmitting apparatus for transmitting the power to a power receiving apparatus includes a power transmitting unit configured to wirelessly transmit the power, a receiving unit configured to receive from other power transmitting apparatuses currently transmitting the power the information about the resonance frequencies used for the current power transmission, and a resonance frequency determination unit configured to, based on the resonance frequency information, determine a resonance frequency to be used for power transmission by the power transmitting unit.

A power reception device in a power transmission system including a power transmission device including a primary coil and the power reception device including a secondary coil, the power transmission device being configured to drive the primary coil and transmit AC power corresponding to a clock signal which is frequency-modulated according to a binary data signal, the primary coil and the secondary coil being electromagnetically coupled together to receive by the secondary coil in the power reception device, the AC power transmitted from the power transmission device, comprises a clock-signal extraction circuit configured to extract the clock signal from an induced voltage induced at one end of the secondary coil in receiving the AC power; and a demodulation circuit configured to generate a pulse synchronously with the clock signal extracted by the clock-signal extraction circuit, and demodulate the pulse to obtain the binary data signal.

In a general aspect, a method for transmitting data between an NFC card and an external NFC device via a selected interface (e.g., contact or contactless), and further via a contactless interface of the NFC module when the contact interface of the NFC card is selected can include using an NFC card that includes an antenna circuit having an antenna coil with a magnetic axis and an electrically conductive screen extending near the antenna coil. The magnetic axis of the antenna coil can be substantially parallel to a plane defined by the NFC card and not cross the conductive screen. The contactless interface of the NFC card, when selected by the NFC card, can emit data by emitting bursts of magnetic field from the antenna coil, so as to compensate for effects of the conductive screen on a maximum distance for transmitting data by load modulation.

A communication system may include a first broadband device and a second broadband device. Signals may be wirelessly communicated from the first broadband device to the second broadband device at a power level that is below a spurious emissions mask. The communicated signals may be transmitted over a designated frequency band. A barrier separates the first broadband device from the second broadband device. The first broadband device may be paired with the second broadband device, and the signals may be wirelessly communicated from the first to the second broadband device. The signals may be communicated using signal emitting/receiving components, which may be jointly configured to optimize near-field communication while nullifying or substantially reducing signaling in other ranges, particularly far-field or intermediate-field ranges. The signal emitting/receiving components may comprise dipole or coil antennas, with the desired optimization and nullification being achieved based on controlling of electromagnetic fields.

An image processing apparatus includes an operation panel, a near field communication portion, and a hardware processor. The operation panel is attached to a main body of the image processing apparatus such that a position relative to the main body is variable. The near field communication portion is arranged in the operation panel and carries out near field communication with a terminal by receiving radio waves transmitted from the terminal. The hardware processor is configured to change a communication distance in near field communication with the terminal through the near field communication portion in accordance with a position of the operation panel.

An electrical power and/or electrical signal transmission system for transmitting electrical power and/or electrical signals from a location on a first side of a metallic wall to a location on a second side of the metallic wall includes a transmitting apparatus having an electrical source and a first transformer. A receiving apparatus has a receiving module for receiving electrical power and/or electrical signals and a second transformer. First and second ends of a primary winding of the second transformer are electrically connected to respective spaced locations on the second, opposite, side of the metallic wall for picking up electrical power and/or electrical signals from the metallic wall. The receiving module is electrically connected to a secondary winding of the second transformer to enable electrical power and/or electrical signals to be transmitted from the electrical source to the receiving module.

A wireless device is disclosed that includes an antenna system comprising at least one inductive element and two or more capacitive elements. A switching component configured to change a circuit configuration of the capacitive elements. A controller configured to transmit a signal using the antenna system and to receive a response from a first device, to determine a communications protocol associated with the first device and to change a configuration of the antenna system in response to the detected communications protocol by actuating the switching component.