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

Abstract

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 T M 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%.INDEX TERMS 3D-printed ceramic filter, additive manufacturing, alumina 3D printing, dielectric TM dualmode filter, monolithic ceramic filter.

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

“…The debinding and sintering steps are done at high temperatures up to 1650 • C and shrinkage of the parts occurs, which needs to be compensated for at the print step. The values of shrinkage compensation used for the HP350 were taken as 1.233 in XY and 1.273 in Z direction [15]. Depending on the geometry, these values may need to be adjusted slightly for more accuracy once the final part dimensions are measured.…”

“…Another example is the approach of manufacturing ceramic monoblock filters, which has received a lot of interest as it requires in the ideal case only metallisation and minimal assembly. Examples of various TM single and dual-mode printed filters are provided in [13]- [15]. Metallisation and manufacturing tolerances proved challenging in [13], [14].…”

“…Metallisation and manufacturing tolerances proved challenging in [13], [14]. In reference [15], more success was achieved by the inclusion of a metal mask/backplate on which the tuning elements could be attached so that the manufacturing defects could be more easily compensated. In [16], the ability to print variable dielectric constants inside waveguide structures to achieve bandpass filtering was proposed.…”

Strength of additively manufactured alumina with different debinding and sintering heat treatments

“…Additive manufacturing (AM), also known as threedimensional printing, is a rapidly growing area of interest due to its potential for reducing costs, achieving complex part geometry, and cutting production times. 1,2 Ceramic AM is enabling technologies, including bioceramic scaffolds, 3 auxetic metamaterials, 4 microwave filters, 5 Luneburg lenses, 6 microreactors, 7 and casting cores. 8 Lithography-based ceramic manufacturing (LCM) has emerged as a leading ceramic AM technique for its ability to create high-resolution, relatively large parts in reasonable print times.…”

A 3-D-Printed Dielectric Resonator for Triple-Mode Applications

“…Therefore, it is important to investigate miniaturization methods for these types of filters while working to maintain high-quality factors and dynamic filtering responses. Many approaches to miniaturization exist, such as the use of dielectric resonators, which reduce the structural size by compressing the electromagnetic fields [1], metamaterials [2], and multimode monoblock filters [3]. In a recent work on utilizing ceramic additive manufacturing (AM) for dielectric combline resonators [4], the quality factor performance of higher modes was increased and dual-mode operation was achieved through changes in the geometry.…”