Printed RGW 3-dB Backward Coupler for Millimeter Wave Applications

This work introduces a flat coupling backward-wave directional coupler based on a printed ridge gap waveguide (PRGW) technology for mm-wave applications. The construction of the proposed coupler is based on a coupled PRGW lines connected by a central rectangular junction. The coupler is demonstrated to have 8% relative bandwidth at 30 GHz. The prototype of the proposed coupler is fabricated and measured, where the measured and simulated results show good agreement.