Monostatic multibeam radar sensor device for a motor vehicle

A method for operating a monostatic multibeam radar sensor device for a motor vehicle, the method comprising:

• switching a directional characteristic, which is a transmission sum pattern (Σ, Σ′) of the multibeam radar sensor device, between two states to obtain additional information;
• wherein the monostatic multibeam radar sensor device for a motor vehicle includes:
• the directional characteristic of an antenna unit, which has at least one transceiving channel (TX) and at least one receiving channel (RX);
• a mixer system, which includes at least an approximately isolating mixer for at least one of the receiving channels (RX), wherein the at least approximately isolating mixer includes a Gilbert cell mixer, which, due to an non-ideal isolation between an input of the local oscillator signal (LO) and the corresponding receiving channel (RX), emits a transmission power via this receiving channel, using an overcoupling signal, wherein the transmission power influences the directional characteristic of the antenna unit, and wherein the directional characteristic is switchable by controlling the phase position of the overcoupling signal.