3D-Printed Dielectric Resonators for Quasi-TE112 Mode Singlets, Doublets and Dual-Mode Filters

This paper demonstrates the use of a ceramic stereolithography-based additive manufacturing process to fabricate higher-order mode dielectric resonators. In this work, dielectric resonators with concentric rings around a combline rod structure are 3D-printed using alumina. The integration of the concentric rings for the use of the TE112 mode allows for a more compact cavity structure and a higher unloaded quality factor when compared to a simple dielectric combline resonator with a similar S-parameter response. The achievable improvements in quality factor for the TE112-mode resonators utilising concentric rings are compared through simulations and experimental results. The measured results demonstrate an increased average in the unloaded quality factor of Qu≈2172 which is approximately 44%. Additionally, the application of the 3D-printed resonators is further demonstrated in a TE112 singlet, doublet, and dual-mode filter configuration.