Abstract: An apparatus for operating at least two antennas for a motor vehicle. The apparatus has a switching device to be coupled to the at least two antennas and to perform at least one switching process for changing a respective input capacitance of one antenna of the at least two antennas. A multiplexing device is configured to select one of the at least two antennas for near field communication and to connect it to an output. The multiplexing device and the switching device are configured, when changing over from a first antenna having a first input capacitance to a second antenna having a second input capacitance, to match the second input capacitance to the first input capacitance by performing the switching process.

Abstract: A charging device for charging an energy storage device of a portable electric device. The charging device has a load cell or load cells, each load cell is equipped with a controllable resonant circuit for inductively transmitting energy, a parallel resonant circuit with two coils and a controllable supply voltage, two controllable switching elements for a self-oscillation of the parallel resonant circuit, which have control connections that can be connected to each other via a respective controllable switch-off element, and a demodulator connected to an output of the load cell being formed by a coil end of one coil of said two coils, wherein said coil end is not connected to a coil end of another coil of said two coils. The self-oscillation can be interrupted in a controlled manner by switching the two controllable switching elements in order to modulate an amplitude of an electromagnetic field generated by the two coils.

Abstract: An apparatus for operating at least two antennas for a motor vehicle. The apparatus has a switching device to be coupled to the at least two antennas and to perform at least one switching process for changing a respective input capacitance of one antenna of the at least two antennas. A multiplexing device is configured to select one of the at least two antennas for near field communication and to connect it to an output. The multiplexing device and the switching device are configured, when changing over from a first antenna having a first input capacitance to a second antenna having a second input capacitance, to match the second input capacitance to the first input capacitance by performing the switching process.

Abstract: A charging device for charging the energy storage device of a portable electric device. The charging device has a load cell or load cells with a controllable resonant circuit for inductively transmitting energy, a parallel resonant circuit with two coils and a controllable supply voltage, two controllable switching elements for a self-oscillation of the parallel resonant circuit, which have control connections that can be connected to one another via a respective controllable switch-off element, and a demodulator connected to an output of the load cell being formed by a coil end that is not connected to the other coil end. The self-oscillation can be interrupted in a controlled manner by switching the controllable switching elements in order to modulate the amplitude of the electromagnetic field generated by the coils.