The invention relates to a transition from a stripline to a waveguide, wherein: the stripline, preferably a microstrip line, is located on a substrate; an upper side of the substrate has a metallised surface and the lower side of the substrate has a metal layer, preferably a high-frequency ground-potential layer; the upper side and the lower side are connected to vias; and at least part of the metallised surface on the upper side of the substrate acts as a waveguide wall.