Quadrature/Non-Quadrature Branch Line Coupler with Equal/Unequal Power Division

This work provides a computer-aided design solution for non-quadrature (or quadrature) branch-line couplers with unequal (or equal) power divisions. The design application provides three topological choices: lumped, distributed and mixed (a combination of lumped and distributed). Each topology mainly has T and $\Pi$ sub-topologies. In addition, transmission line and stepped line topologies are included in distributed topology. The underlying design algorithms are developed using the Y-matrix method. The scattering parameters analysis of the designed coupler is also based on the Y-matrix method.