Novel miniaturized multiband bandstop filters based on asymmetric
multimode resonators Loaded with tree-shape branches
Abstract
In this letter, the operating mechanism of proposed bandstop filters
with asymmetric multiple-mode resonator loaded with tree-shape branches
is introduced. Based on the design procedure, centre frequencies of the
proposed bandstop filters can be controlled due to the designed degree
of freedom. Meanwhile, the proposed BSFs feature compact sizes and sharp
roll-off skirts for transition bands. To validate the design and
analysis, a prototype filter has been fabricated with six stopbands
centered at 1.91/2.38/3.54/5.19/ 5.79/6.85 GHz. The measured results of
the fabricated filter agrees well with the simulation, which shows that
the proposed structure is a good candidate for multi-band BSF designs
and validates the proposed design flow well.