Substrate integrated waveguide six-port broadband front-end circuit for millimeter-wave radio and radar systems

A novel multi-purpose integrated planar six-port front-end circuit combining both substrate integrated waveguide (SIW) technology and integrated loads is presented and demonstrated. The use of SIW technology allows a very compact circuit and very low radiation loss at millimeter frequencies. An integrated load is used to simplify the fabrication process and also reduce dimensions and cost. To validate the proposed concept, an integrated broadband six-port front-end circuit prototype was fabricated and measured. Simulation and measurement results show that the proposed six-port circuit can easily operate at 24 GHz for radar systems and also over 23-29 GHz for broadband millimetre-wave radio services.