Design of dual-band bandpass filters using stepped-impedance resonators

Abstract

In this paper, a new coupling configuration of the stepped impedance resonator (SIR) has been presented to design dual-band bandpass filters with the small circuit size. We design the filter with higher selectivity based on SIR directing-coupling, cross-coupling, input and output external quality factors. Through resonance characteristics of a SIR, the second resonant frequency can be tuned by adjusting structure parameters. The agreement between measured results and full-wave simulation prediction validates the feasible configuration of the proposed filters.