Wideband Bandpass Filter with Controllable Bandwidth and High Selectivity Using Dual-behavior Resonators and Coupled Lines

In this article, a novel wideband bandpass filter with controllable bandwidth and high selectivity using dual-behavior resonators (DBRs) and coupled lines (CLs) is proposed. The filter has a symmetrical structure consisting of a parallel-coupled line and two identical open-ended stubs. The center frequency and relative bandwidth of the filter can be determined by the parallel-coupled line. And two transmission zeros (TZs) near the passband can be adjusted by using open-ended stubs, which enhances the passband selectivity of the proposed filter. In order to testify the advantages of the proposed filter, theoretical analysis and simulation are carried out. As a result, the Electromagnetic (EM) simulation shows that the filter has five zeros and three poles. Thus, the filter has high selectivity.