Substrate integrated waveguide differential filtering power divider with good common-mode suppression and high selectivity

A filtering differential power divider based on the substrate integrated waveguide (SIW) technology is proposed for the first time, featured by good common-mode suppressions and high selectivity. A rectangular SIW cavity, which is connected with differential inputs and operates in a balanced diagonal TE₁₀₂ mode, is utilised to achieve the power division function. It also works with rectangular SIW cavities, which resonate in balanced TE₁₀₂ modes, to obtain good common-mode suppressions for all cases. Meanwhile, electric negative cross-couplings are introduced to improve the frequency selectivity of the proposed filtering power divider. A prototype operated in the X-band has been developed for a demonstration. Good agreement between simulated and measured results is obtained.