IEEE Journal of Microwaves (Jan 2022)

Ceramic Additive Manufactured Monolithic X-Shaped TM Dual-Mode Filter

  • Daniel Miek,
  • Michael Hoft,
  • Jose Antonio Lorente,
  • Andre Berger,
  • Dominik Brouczek,
  • Martin Schwentenwein,
  • Ana Brandao,
  • Petronilo Martin-Iglesias,
  • Vittorio Tornielli di Crestvolant

DOI
https://doi.org/10.1109/JMW.2022.3167250
Journal volume & issue
Vol. 2, no. 3
pp. 496 – 506

Abstract

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This paper presents a monolithic 3D-printed ceramic X-shaped dual-mode microwave filter. The filter is manufactured utilizing a lithography-based ceramic manufacturing (LCM) process, allowing the realization of the resonator as well as the housing in one single piece. Therefore, contact as well as alignment problems, usually arising between a ceramic in $TM$ mode operation and a metallic enclosure, can conveniently be avoided. A fourth order dual-mode filter with a designed center frequency of 6 GHz and a bandwidth of 279 MHz is realized in alumina material. Practical design rules to be considered in the filter layout process as well as limitations imposed by the LCM approach are discussed. The outer surface of the ceramic cavity is subsequently metallized using a silver spray-coating. Advantageously, the metallization is only a few micrometers thick, wherefore the weight of the component can be reduced. The measurement results are compared to the simulation and reveal good agreement. A temperature stability measurement shows a center frequency downward shift of 0.22%.

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