Singlets, cascaded singlets, and the nonresonating node model for advanced modular design of elliptic filters

The singlet, which contains one resonator and generates one transmission zero, is introduced as the most basic building block for modular design of elliptic filters. Higher-order elliptic filters are designed by cascading singlets to generate the required transmission zeros. A novel model, the nonresonating node model (NRNM), which contains both resonating and nonresonating nodes is then introduced. The model allows a high level of modularity in the design of elliptic filters. Example filters are designed and measured to validate the model and the design approach.