Dual-polarization beam forming networks based on high order directional couplers

A Ka-band dual-polarization 3 dB directional coupler is designed for Beam Forming Network applications. The proposed solution is particularly suited for compact Nolen networks. Nolen architecture is attractive because it is planar and lossless. Two parallel square waveguides are coupled through an array of apertures, designed to get the desired coupling and high isolation between the two orthogonal polarizations.