The invention relates to a multibeam antenna for emitting/receiving a radiofrequency signal in a plurality of directions in at least one frequency band, the antenna including: a floorplan (P); a dielectric substrate (11) having a permittivity (∈1), the substrate (11) being arranged on the floorplan (P); and a plurality of assemblies (Ei) of antenna elements arranged on the substrate (11), each assembly (Ei) corresponding to a direction of the antenna. The antenna according to the invention is characterized in that said antenna also includes a dielectric superstate (12), having a higher permittivity (∈2) than the permittivity (∈1) of the substrate (11), arranged on the assemblies (Ei) of antenna elements, and in that the assemblies (Ei) are interleaved one under the other so as to form a column, the assemblies (Ei) corresponding to a single antenna direction being separated by a number of assemblies equal to the number of antenna directions.