Design of Quasi-Elliptic Function Filters with Dual-Passband Responses and Multi-spurious Suppression

This paper presents a design method for quasi- elliptic function filters with dual-passband responses and multi- spurious suppression. The filters are composed of compact miniaturized hairpin resonators in cross-coupled arrangement. The hairpin resonators are of stepped-impedance-resonator (SIR) form. All resonators in a filter have same fundamental and first higher order frequencies centered at the two design passbands, but separate other higher order resonant frequencies. Several filters are fabricated and measured. The results show a good agreement with the simulation.