The so-called FBS concept for beam shaping is based on binary phase plates and can be used to generate Top-Hat profiles in the working plane. In addition, there are already theoretical considerations to use this concept for increasing the depth of field of a Gaussian laser beam. Within the scope of this work, we show the theoretical propagation behavior through free space behind such a diffractive optics and relate characteristic propagation effects to the Rayleigh length of the initial beam used. From knowledge gained, we derive instructions as to what needs to be considered when integrating such elements into optical systems. Furthermore, experiments results will be presented that demonstrate the propagation behaviour in free space, a possible adjustment of Top-Hat size and the increase of the depth of field of a Gaussian laser beam.