Radar fill level measuring device for determining a fill level of a medium, the radar fill level measuring device comprising: a radar module for generating a transmission signal having a transmission frequency of at least 60 GHz; and at least one antenna coupled to the radar module for transmitting the transmission signal to a surface of a medium and for receiving a received signal reflected at the surface; wherein the radar module comprises: - a phase-locked loop comprising an oscillator for outputting an output signal at an output (19, 21) of the oscillator, a phase detector and a frequency divider coupled between the output (19, 21) of the oscillator and an input of the phase detector for generating a frequency-divided signal based on the output signal of the oscillator; and - a transceiver coupled between the oscillator and the antenna for separating the transmission signal and the received signal, wherein the output signal of the oscillator has an output frequency of at least 60 GHz; wherein the output (19, 21) of the oscillator is directly connected to an input of the transceiver, so that based on the output signal of the oscillator the transmission signal can be radiated via the antenna; wherein the frequency divider and the transceiver are coupled to the same output (19, 21) of the oscillator; wherein the phase detector includes a reference input for receiving a reference frequency signal and a phase detector output coupled to a control input of the oscillator; and wherein the phase detector is configured to determine a phase difference between the reference frequency signal and the frequency-divided signal and to output, at the phase detector output to the control input of the oscillator, a control signal correlating with the determined phase difference for controlling the output frequency of the output signal of the oscillator. a radar module for generating a transmission signal having a transmission frequency of at least 60 GHz; and at least one antenna coupled to the radar module for transmitting the transmission signal to a surface of a medium and for receiving a received signal reflected at the surface; wherein the radar module comprises: - a phase-locked loop comprising an oscillator for outputting an output signal at an output (19, 21) of the oscillator, a phase detector and a frequency divider coupled between the output (19, 21) of the oscillator and an input of the phase detector for generating a frequency-divided signal based on the output signal of the oscillator; and - a transceiver coupled between the oscillator and the antenna for separating the transmission signal and the received signal, - a phase-locked loop comprising an oscillator for outputting an output signal at an output (19, 21) of the oscillator, a phase detector and a frequency divider coupled between the output (19, 21) of the oscillator and an input of the phase detector for generating a frequency-divided signal based on the output signal of the oscillator; and - a transceiver coupled between the oscillator and the antenna for separating the transmission signal and the received signal, wherein the output signal of the oscillator has an output frequency of at least 60 GHz; wherein the output (19, 21) of the oscillator is directly connected to an input of the transceiver, so that based on the output signal of the oscillator the transmission signal can be radiated via the antenna; wherein the frequency divider and the transceiver are coupled to the same output (19, 21) of the oscillator; wherein the phase detector includes a reference input for receiving a reference frequency signal and a phase detector output coupled to a control input of the oscillator; and wherein the phase detector is configured to determine a phase difference between the reference frequency signal and the frequency-divided signal and to output, at the phase detector output to the control input of the oscillator, a control signal correlating with the determined phase difference for controlling the output frequency of the output signal of the oscillator.