Researchers at Tomsk State University have developed a composite filament for standard FDM 3D printers that behaves not just like plastic but also as a narrowband electromagnetic filter. Printed parts made from this material demonstrated selective absorption of signals around 49 GHz-frequencies close to the millimeter-wave range widely used in radar and next-gen communication systems. This breakthrough enables embedding filtering functions directly into 3D-printed components without additional assembly.

The base polymer is ASA, prized in 3D printing for its weather resistance and heat stability. The scientists enhanced it by mixing in barium hexaferrite powder, a magnetic ceramic commonly found in microwave components and permanent magnets. Tomsk’s radio physicists then tested the composite’s mechanical strength, magnetic properties, and behavior in the super-high-frequency (SHF) band near 49 GHz.

A key finding is that the barium hexaferrite filler retains its electromagnetic filtering properties even after passing through extrusion and the FDM printing process. Increasing the ferrite content boosts the part’s ability to dampen signals near 49 GHz but also weakens its mechanical durability. The team had to strike a careful balance, optimizing both material strength and radiofrequency performance to achieve a practical composite filament.

Associate Professor Alexander Badyin from Tomsk State University’s Radioelectronics Department explains that their work proves ferrite powder can function as a narrowband filter embedded directly into a finished 3D-printed part. The university controls the entire production cycle-from synthesizing the ferrite powder to blending the composite and manufacturing filament on their in-house extrusion line. This setup allows rapid adjustments to the formula to optimize the filter’s response frequency and durability.

This innovation arrives as functional materials are becoming the main growth driver in 3D-printed electronics, moving beyond purely cosmetic parts. FDM remains the cheapest and most accessible additive manufacturing method worldwide. Current research explores printing conductive polymers, dielectrics, and metamaterials for antennas, sensors, and electromagnetic shielding. Tomsk State University’s composite filament adds a new dimension by enabling RF filtering properties embedded during filament fabrication itself.

Embedding narrowband microwave filters into 3D-printed components could transform how radio devices and sensors are manufactured, potentially streamlining production and reducing costs. The challenge ahead is scaling this composite for practical applications and integrating it within complex electronics. It will be interesting to see if this approach competes with established techniques from major players like Apple, Samsung, or Google, who tend to rely on traditional fabrication and layered chip designs for RF components.

Composite filament for 49 GHz electromagnetic filtering in FDM 3D printing

The composite filament developed at Tomsk State University consists of:

• ASA polymer base, known for heat and weather resistance
• Barium hexaferrite powder, a magnetic ceramic with microwave filtering properties
• Optimized ferrite content balancing electromagnetic attenuation near 49 GHz and mechanical durability

After extrusion into filament and printing via standard FDM printers, the material selectively absorbs electromagnetic signals in the super-high-frequency band around 49 GHz, useful for radar and next-generation communication systems.

Applications and future outlook for 3D-printed electromagnetic filters

Potential uses of this technology include integrating narrowband electromagnetic filters directly into radio electronics, antennas, and sensors during the manufacturing process. This integration could reduce component count, assembly complexity, and overall device size and cost.

The next steps involve scaling production of the composite filament and developing methods for embedding these filters into more complex 3D-printed electronic devices. Competing with established RF manufacturing methods used by tech giants will require demonstrating advantages in cost, performance, and customization.