Abstract: The radar has two antennas which radiate RF signals of different frequencies and whose radiation patterns overlap. The frequencies of the radiated signals are generated by amplitude-modulating a single RF signal with two low frequency signals. The signals received by one of the two antennas are evaluated by determining, in an evaluating device, the difference between the amplitudes of the RF signals of different frequency which are reflected from an object. A DC voltage signal proportional to the above difference is generated and the DC voltage signal is fed to a threshold circuit whose threshold is determined by a predetermined azimuth range. Therefore, it can be determined if the reflecting object is in the same road lane as a car equipped with the radar.