A broadband transition coupling for transition between a waveguide and a printed circuit board with a substrate integrated waveguide is disclosed. The broadband transition coupling comprises a main body that encompasses an air-filled waveguide section and a transition section. The air-filled waveguide section comprises a first interface for the waveguide. The transition section provides a second interface for the printed circuit board. The transition section continuously tapers along the second interface in order to reduce a height of the transition section for transition coupling with the printed circuit board. Further, the present disclosure relates to a broadband system for processing electromagnetic signals.