PROJECT TITLE :

Compact sext-band bandpass filter based on single multimode resonator with high band-to-band isolations

ABSTRACT:

On the basis of one multimode resonator (MMR), a miniaturised microstrip sext-band bandpass filter (BPF) with high band-to-band isolations has been presented. The proposed MMR is an stepped impedance resonator (SIR) with one short-circuited stub loaded in the middle and 2 identical open-circuited stubs located at 2 sides. Transmission poles (TPs) and transmission zeros (TZs) will be excited when the electrical lengths of 2 open stubs increase. The TZs introduced by open stubs separate the TPs into multiple groups; thus, the design of a sext-band BPF becomes accessible. Moreover, two input/output tapped branches and radical stub-loaded short-circuited lines are treated as perturbation structures in order to increase design freedoms for improving filter performance. Sensible agreement between simulated and measured results validates the design method.