Abstract: A radar sensor includes a transmitter module, a receiver module, and a lens device. The transmitter module has a transmitter-side patch array antenna and transmits radar signals with a first directivity. The receiver module has a receiver-side patch array antenna and receives the radar signals reflected in the detection area. The lens device has a first lens for the transmitted radar signals and a second lens for the reflected radar signals. The second lens is arranged substantially directly adjacent to the first lens in a direction of a length extension in a top view. The first lens and the second lens are designed so that a ratio between the length extension and a width extension of the first directivity of the radar signals or a second directivity of the radar signals is influenceable, i.e., the radar signals with the first directivity are convertible into radar signals with the second directivity.