3D printing and metalization methodology for high dielectric resonator waveguide microwave filters

This paper presents a novel approach to manufacture and metalize a standard waveguide microwave filter, with a high dielectric resonator inserted in it. As a first step, a set of 3D-printed ABS plastic filaments have been measured, to establish their electrical properties and suitability for microwave design. Subsequently, a new commercial silver conductive lacquer has been tested to metalize a standard hollow WR-90 waveguide, printed by Fused Deposition Modeling (FDM) technique. This lacquer furnishes acceptable conductivity and proper shielding of the electromagnetic fields inside the structure, operating among microwave frequencies. In parallel, a special thin pellet, chemically synthesized, has been investigated and fabricated. This small cylindrical rod behaves like a high dielectric resonator, that has been employed to design a highly selective waveguide microwave filter, paving the road to the implementation of a novel class of microwave components and systems.