A novel dual-band bandpass filter using microstrip stub-loaded two-mode resonators with source and load coupling

In this paper, a compact microstrip dual-band BPF using stub-loaded two-mode resonators is developed. The midband frequencies of the two passbands can be adjusted separately. Furthermore, four transmission zeros are yield in the stopband of the filter by introducing direct coupling between the source and load of the filter. Significantly improved skirt properties of the dual-passbands are accomplished, and very wide stopbands are obtained.