ID transponder for a wireless vehicle locking system, said ID transponder comprising: a battery, a microcontroller which is coupled to the battery, an ultra-wideband transceiver coupled to the microcontroller for being controlled by the microcontroller, wherein the ultra-wideband transceiver is coupled to the battery in parallel with the microcontroller via a UWB coupling path, characterised in that a switching means is in place in the UWB coupling path, the switching means being controllably coupled to the microcontroller such that the microcontroller controls the switching means to establish and release a continuous galvanic coupling of the ultra-wideband transceiver along the UWB coupling path to the battery, wherein an energy management circuit is formed which is coupled to the UWB coupling path, the energy management circuit being adapted to limit the current conducted through the UWB coupling path, wherein a first buffer capacitance is coupled to the UWB coupling path and the battery, wherein the energy management circuit is coupled to the first buffer capacitance and senses a first buffer voltage at the first buffer capacitance, wherein the power management circuit is coupled to the microcontroller and is adapted to transmit status information at least with respect to the first buffer voltage to the microcontroller, wherein a second buffer capacitance is coupled to the ultra-wideband transceiver and the battery, wherein the ultra-wideband transceiver has at least two voltage inputs, a first of which is fed via the UWB coupling path and the first buffer capacitance and a second of which is fed via the second buffer capacitance, wherein a DC voltage converter is coupled between the UWB coupling path and the second buffer capacitance, which is adapted to generate a second buffer voltage from the first buffer voltage and to charge the second buffer capacitance with the second buffer voltage. a battery, a microcontroller which is coupled to the battery, an ultra-wideband transceiver coupled to the microcontroller for being controlled by the microcontroller, wherein the ultra-wideband transceiver is coupled to the battery in parallel with the microcontroller via a UWB coupling path, characterised in that a switching means is in place in the UWB coupling path, the switching means being controllably coupled to the microcontroller such that the microcontroller controls the switching means to establish and release a continuous galvanic coupling of the ultra-wideband transceiver along the UWB coupling path to the battery, wherein an energy management circuit is formed which is coupled to the UWB coupling path, the energy management circuit being adapted to limit the current conducted through the UWB coupling path, wherein a first buffer capacitance is coupled to the UWB coupling path and the battery, wherein the energy management circuit is coupled to the first buffer capacitance and senses a first buffer voltage at the first buffer capacitance, wherein the power management circuit is coupled to the microcontroller and is adapted to transmit status information at least with respect to the first buffer voltage to the microcontroller, wherein a second buffer capacitance is coupled to the ultra-wideband transceiver and the battery, wherein the ultra-wideband transceiver has at least two voltage inputs, a first of which is fed via the UWB coupling path and the first buffer capacitance and a second of which is fed via the second buffer capacitance, wherein a DC voltage converter is coupled between the UWB coupling path and the second buffer capacitance, which is adapted to generate a second buffer voltage from the first buffer voltage and to charge the second buffer capacitance with the second buffer voltage.