Research on the Hyperbola Type Graded Dumbbell Coaxial Resonator and its Filter Design

The paper presented a novel kind of hyperbola type graded dumbbell coaxial resonator (HT-GDCR), which can also provide the superiority of GDCR. That is, the HT-GDCR can achieve miniaturization while maintaining high- Q values. To understand GDCR better, the resonator features of HT-GDCR and parabola type GDCR (PT-GDCR) were compared with the same sizes. Subsequently, the HT-GDCR was deployed to design a classical inline four-pole bandpass filter for more validation. 3D metal printing technology was used to fabricate the designed filter for fast experimental demonstration. As a result, the tested results agreed well with the simulated ones.