Additive Manufacturing of Zirconia Dielectric Resonator Filters Produced by Direct Ink Writing of Particles with Bimodal Size Distribution

Dielectric filters made with additive manufacturing have received attention because even complex geometries can be manufactured. However, the fabrication using, e.g., zirconia is difficult because of the necessity to remove pores with hot isostatic pressing. Here, we present the direct ink writing method of zirconia using more than one particle size to receive dense parts without the need for hot isostatic sintering. To validate this manufacturing process for the production of ceramic resonators for filter applications, the relevant properties, permittivity and loss tangent, are determined. A third order filter made of additively manufactured dielectric TE01 delta mode resonators exhibits an unloaded quality factor of Q(0) = 1050 as first demonstrator. It proves the potential of the process used for the cost-effective manufacture of dielectric resonator filters which could also have more complex geometrical structures in future.