An integrated radio-frequency circuit for a radar sensor, having a clock input that is designed to receive a clock signal produced externally to the integrated radio-frequency circuit, having a local oscillator that is designed to produce a local radio-frequency signal, having a radio-frequency input that is designed to receive an external radio-frequency signal produced externally to the integrated radio-frequency circuit, and having a changeover switch that is coupled to the local oscillator and to the radio-frequency input and is designed to change over between the local radio-frequency signal and the external radio-frequency signal for the production of a radar signal. In addition, a corresponding radar sensor and a corresponding operating method, are also described.