Dual-band bandpass filters using open-/short- circuited stub-loaded quarter-wavelength resonators

Abstract

Two different types of tunable dual-band bandpass filters (BPFs) based on a pair of open-/short-circuited stub-loaded quarter-wavelength resonators, which share a common short-circuited via hole as a K-inverter, have been presented. Additionally, a source/load cross coupled-line configuration is introduced to improve the frequency selectivity of the proposed filters. These two dual-band BPFs have been demonstrated with good simulated results, which are realized by tuning the configuration of the proposed filter.