Quad-mode and dual-mode dielectric resonator filters

This paper introduces for the first time a quad-mode dielectric resonator filter, using a simple cylinder resonator. A four-pole single cavity filter is designed, simulated, and fabricated based on this quadruple mode resonator. Additionally, a new type of dual-mode dielectric resonator filters is introduced, using the same cylindrical resonator cut in half along its axis. Center frequency control, intra/inter/input-coupling mechanisms, tuning, and spurious improvement methods are discussed, showing versatility of the proposed structures to realize different filtering functions and specifications. Measured results are presented for practical filters, employing the proposed quad-mode and dual-mode resonators. The dielectric resonator filters presented in this paper offer a significant size and mass reduction in comparison with conventional dielectric resonator filters. They promise to be useful for both wireless and satellite applications.