Optimum resonant conditions of stepped impedance resonators

Resonant conditions for a stepped impedance resonator have been completely analyzed in this study. Contrary to the graphic method to characterize the properties of a stepped impedance resonator, the analytic optimum solutions for the fundamental and the first spurious modes have been derived. Moreover, the condition for a stepped impedance resonator with a widest spurious-free upper stopband has also been investigated. With these efforts, this type of resonators can be designed with the exact parameters, not the rough estimate values from the characteristic curves, in the initial stage.