Compact dual-band bandpass filter using a novel dual-mode resonator

A novel dual-mode resonator is applied to a compact dual-band bandpss filter (BPF) with wide stopband. In addition, in order to increase the degree of freedom for the dual band filter design, the feeding structure employs parallel coupled lines. Moreover, with the aid of source-load coupling, transmission zeros can be created close to the upper passband edges, resulting in high skirt selectivity. This paper deals with the analysis and design of the proposed dual-band BPF as well as the experimental validation of the predicted dual-band performance. It is found that the simulated and measured results are in good agreement.