Studies on Additive Microfabrication of the Millimeter-band Components by LCD 3D Printing and Magnetron Sputtering

We propose a technology based on the liquid crystal display (LCD) 3D printing and magnetron sputtering for rapid and low-cost fabrication of millimeter-band electromagnetic components. To verify the proposed approach, D- and H-band straight waveguide sections were fabricated. Magnetron sputtering was used to deposit a thin copper film onto the inner surface of the fabricated structures. Morphology and profilometry studies revealed that the fabrication tolerance corresponds to the pixel size of the LCD screen in the used 3D printer, while the surface roughness is less than 500 nm with a metallization layer thickness of 5 $\mu \mathrm{m}$ . For the D-band 3D-printed samples, measured reflection loss was not worse than 20 dB, while the transmission loss was around 1–2 dB/cm. The reflection loss for the H-band samples was found to be around 15 dB, while the transmission loss ranged from 3 to 5 dB/cm. Several ways to decrease the transmission loss will be discussed.