Performance and Design of Double Coaxial Stepped Impedance Resonators for Mobile Communication

An improved accurate model for stepped impedance resonators with a double coaxial structure (DC-SIRs) is proposed in this paper. The step discontinuities of the DC-SIRs have been fully considered in the model. The resonance frequency calculated by the improved accurate model agrees well with the measured results. The band-pass filters have been designed using the accurate model of DC-SIRs and show excellent performances such as more compact size, lower insertion loss and it can be used for lower frequencies.