The next standard for mobile Internet and mobile telephony is on the horizon: 5G. South Korea, Switzerland and some US cities are already using 5G, while other countries are in the introductory phase. However, the electronics needed to transmit and receive the signals require much finer structures than before. This also applies to the associated antennas, which will initially operate at 3.6 GHz and later at higher frequencies. However, the thick-film technology used to date has reached its limits in terms of miniaturization: with a resolution of around 50 micrometers, the limit has been hit, at least as far as industrial implementation is concerned. For 5G, 20 µm or finer structures are required.
Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden have been able to solve this challenge in cooperation with the British company Mozaik. They developed a technique with which conductor paths can be produced with a structural resolution of 20 µm and smaller - and, as Fraunhofer scientist Dr. Kathrin Reinhardt assures, "suitable for mass production and industry". It is said that the investment costs are low.
Conventional screen printing technology is used as the basis - so users can continue to use their systems as usual. The principle of screen printing: A screen with the desired printing structure is positioned over a substrate, a thick-film paste is applied through the screen openings and the desired printing structure is transferred. The deposited layer is then dried and sintered at high temperatures to produce the final functional layer properties. However, since the stainless steel wires used for the screens cannot be produced in any desired thickness, screen printing has reached its limit in terms of structure resolution and quality at 50 µm.