The invention relates to a vehicle assembly including a radar sensor configured to emit radar waves over a range of wavelengths, a luminous module. The luminous module including a sub-layer and a layer of patterns forming a sub-wavelength structured dielectric element with a repetition period of the patterns that is less than a quarter of a wavelength of the range, with the total thickness of the luminous module is equal to m times a wavelength of the range, the whole being divided by twice the equivalent refractive index of the sub-layer and of the layer of patterns, times the cosine of a refracted angle corresponding to an angle of incidence of the radar waves, where m is an integer.