AMetallic Shield-free Tri-mode Dielectric Resonator Filter

In this paper, a tri-mode dielectric resonator filter is implemented with metallic shield eliminated. Owing to the proposed microstrip feeding structure, three resonant modes with good transmission characteristic are excited, flexibly controlled and coupled to implement a tri-mode bandpass filter. For validation, the proposed filter was designed, fabricated, and measured. Good agreement between simulation and measurement can be observed. Compared with the existing dielectric resonator filters, the proposed filter achieve good performance without the introduction of an additional accessory to suppress the radiation.