Dual-layered substrate-integrated waveguide six-port with wideband double-stub phase shifter

A dual-layered six-port front-end circuit on the basis of substrate-integrated waveguide (SIW) technology is presented and demonstrated. The use of SIW technology allows the development of a compact circuit with low radiation loss at millimetre-wave frequencies. The six-port architecture makes use of multilayer couplers that provide a wide coupling area through two slots; a new broadband SIW phase shifter composed of two H-plane stub lines and a reference line; and two SIW power dividers. The six-port design is free from loads as in the case of classic modified six-port architectures with eight ports. To validate the proposed concept, an integrated broadband six-port front-end circuit prototype was designed, fabricated and measured. Simulation and measurement results show that the proposed six-port circuit can easily operate at 60 GHz for V-band system applications. The two-layered structure presents interesting technological features including low profile, small volume and footprint and high-density integration.