Compact SIW Six-Port With Improved Output Matching and Isolation

This contribution presents a compact multilayer substrate integrated waveguide (SIW) six-port junction with embedded carbon resistive films. SIW six-ports usually employ reactive power dividers, which degrade the amplitude and phase balance when the six-port is terminated with mismatched power detectors. The associated impairments are studied and an SIW six-port at K-/Ka-band with improved isolation and output matching is designed to overcome these limitations. Measurements of the fabricated component validate the concept. At 24 GHz, return loss and isolation exceed 19 dB for all ports. The six-port is very compact and can be integrated in multilayer printed circuit boards.