The software SWAN™ is a powerful CAD tool for the design and analysis of very large slotted waveguide arrays having a wide range of capabilities. - SWAN™ is fast, as it makes use of a rigorous equivalent circuit for the single slot obtained with an accurate full-wave analysis. The design and analysis of large arrays with thousands of slots can be easily carried out. - SWAN™ is accurate, as internal and external mutual coupling effects and their dependence on frequency and scanning angle as well as dielectric and metal losses are rigorously taken into account. Feeding network and input transitions can also be considered. - SWAN™ is flexible, as it allows for customizable waveguide dimensions, dielectric filling of the waveguides, many different feeding configurations, beam scanning optimizations, weighted aperture synthesis, etc. The software may be therefore useful in many applications.