Radar sensor device and method for self-testing

A method for self-testing a radar sensor device, the radar sensor device including:

• a radar sensor configured to detect an object using radar waves,
• a transmission path which transmits a transmission signal in a direction of the object and includes a transmission antenna of the radar sensor configured to transmit the transmission signal,
• at least one receiving path which transmits a transmission signal reflected by the object as a reception signal and includes a receiving antenna of the radar sensor configured to receive the reception signal, and
• a test signal path which transmits a test signal for self-testing the radar sensor and extends at least between a first coupling point of the transmission path and a second coupling point of the receiving path, wherein the test signal has a first polarity and the transmission signal has a second polarity different from the first polarity, wherein the test signal path includes a polarity-dependent transmission arrangement which allows transmission of the test signal having the first polarity via the test signal path and blocks transmission of the transmission signal having the second polarity via the test signal path,
• wherein the first coupling point is disposed in the direction toward the object downstream of the transmission antenna or immediately upstream of the transmission antenna, and the second coupling point is disposed in a direction coming from the object upstream of the receiving antenna or immediately downstream of the receiving antenna,
• the method comprising the following steps:
• evaluating the test signal by determining a signal relationship between the reception signal and the received test signal;
• and
• detecting a disturbance of the signal transmission as a function of the signal relationship.