Wideband and spurious-suppressed differential bandpass filter based on strip-loaded slot-line structure

摘要

In this article, a wideband and spurious-suppressed differential bandpass filterbased on strip-loaded slot-line structure is presented. By means of the differentialmicrostrip-slot-line-microstrip transition, the proposed filter has a widebandbandpass filtering response. Simultaneously, the utilization of the strip-loadedslot-line extends its upper stop-band. The proposed bandpass filter has widerupper-stopband, wideband bandpass response, and intrinsic high commonmode(CM) suppression. To verify the design concept, one filter example hasbeen designed, fabricated, and measured. It has a differential-mode (DM) 3-dBfractional bandwidth of 157% with a low 0.82 dB minimum insertion loss.What's more, it shows a very wide 20 dB DM stop-band bandwidth of 6.5 f0d.The experienced results are in good agreement with the theoretical and simulatedresults.