Compact gradually variational stepped impedance resonator band-stop filters

This article proposes a novel gradually variational stepped impedance hairpin resonator. Two band-stop filters are proposed which are using the novel gradually variational stepped impedance hairpin resonator with defected ground structure or not. The filters have many remarkable advantages by using resonators, such as compact size, high selectivity, and simple structure. Good agreement between the simulated results and the measured results is achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1–3, 2014