Ku band filter based on low loss alumina octagonal dielectric resonators made by 3D ceramic stereolithography

This paper presents a new filter topology using alumina dielectric resonators made by 3D ceramic stereolithography. Thanks to the low loss tangent of the alumina used with this manufacturing process (tan δ= 5 10-5 at 15 GHz), high unloaded quality factor of 6500 could be achieved with this dielectric resonators. The resonators with their brass housing have an unloaded Q factor which is about 35% higher than for an equivalent metallic resonant cavity while being 25% smaller. The proposed narrow band two pole filter presents an experimental 1.19% bandwidth at 14.95 GHz demonstrating the validity of the proposed structure.