Design of Post-Wall Waveguide Stacked E-plane Cruciform Cross Couplers for 120-GHz band

An E-plane cross-coupler with a center frequency of 120 GHz that can be fabricated on a multilayer printed circuit board used in a 2D butler matrix has been designed. The basic structure consists of a three-layer waveguide and two slots, coupled at the upper and lower sections and designed not to affect the radio waves in the middle section. The design with post walls resulted in low reflection and high isolation characteristics.