SIW compact diplexer

A compact diplexer fabricated on substrate-integrated waveguide (SIW) technology is presented. The diplexer is a coupled-resonator network with no additional elements such as power dividers, composed exclusively of six SIW resonators coupled through inductive irises, with one transmission zero at each channel that improves the selectivity. The close physical proximity of the resonators and the leakage associated to via-hole walls characteristic of the SIW technology are the main challenge of this design. However, this effect can be taken into account, as proved by a fabricated prototype with pass bands around 8 GHz.