1. Field of the Invention
The present invention relates to a monostatic multi-beam radar sensor and a method for operating such a radar sensor.
2. Description of Related Art
A monostatic multi-beam radar sensor for motor vehicles is known from published international patent application WO 2006/029926 A1, the sensor being made up of a group antenna, a planar lens having a plurality of inputs, and a homodyne mixer system having a plurality of transfer mixers, which are connected in parallel to the inputs of the lens. The lens causes beam bundling both in transmit and in receive operation. The use of such a radar sensor enables parallel processing of the signals from a plurality of radar beams. The transfer mixers can be placed in a tight space on one board.
In various applications, e.g., in ACC (adaptive cruise control), the transmit and receive characteristics must differ. This has previously been achieved with the aid of bi-static antenna systems, e.g., in a DBF (digital beam-forming) radar by a transmit antenna having lower bundling and a receive antenna having strong bundling, or by a mixed system, i.e., using one antenna system for transmitting and receiving radar signals, and another antenna system only for receiving radar signals, as described in published German patent document DE 196 48 203 C2.