Research Of Tunable Bandstop Filter And Dualband Bandstop Filter

As the rapid development of the wireless communication technology, the demand for means of communication becoming diversification. In order to meet different application requirements, such as the dynamic allocation of frequency resources, high frequency spectrum utilization and diversity functional of communication systems, band-stop filters with different performance characteristics are needed. Based on the above application background, this paper focus on the research of tunable band-stop filter and dual-band band-stop filter.Firstly, we proposed a novel defect microstrip structure(DMS) based on improving the existing defect microstrip structure. By analyzing its bandstop features, a narrow band, compact structure, good stop-band rejection characteristics of tunable band-stop filter has been designed and simulated.Secondly, in order to overcome the drawback of conventional reflective tunable filter and the signal transmission power decline of DMS structure, we further studied the absorptive tunable bandstop filter using coupled line resonators. The filter has some significant features, such as high selectivity, high signal power transmission and other characteristics.Finally, we designed a new type of dual-band bandstop filter based on the SIR coupled line resonator structure. Compared with the existing dual-band bandstop filter, the filter has some advantages, such as wide stopband, stop-band frequency ratio easily controlled and simply structure. The effectiveness of the design method is verified through simulation, fabrication and testing.