Of all the magnificent things 3D printing has done for ages, this new application, may dwarf it all – endless possibilities lie beyond its discovery. We may soon witness the creation of a 3D printed polymer (plastic), which has an ability to influence or bend electromagnetic pulses.
What’s the Idea?
The basic concept behind this technology is similar to way a Semiconductor material functions. Semiconductors are materials, which are incapable of transmitting electromagnetic pulses, until “doped” with some other conduction materials; like Ferrous, Copper, etc.
In this case, Ceramic or TiO2 is being used as the “Dope”, to non-conducting polymer or plastic. TiO2, increases the permittivity of the polymer to a value of approx. 7 units. This allows the designing and printing of 3D structures which will have a strong influence on electromagnetic fields. Examples are antennas, or to print wave guiding or filtering structures. As mentioned, for achieving this, polymers are filled with dielectric, magnetic or conductive “Dopes” or fillers.
What are the Applications?
It is possible to locally adjust the fill ratio it is possible to locally vary the permittivity of the resulting material. A 100% fill will lead to a permittivity of 9, which can be reduced to nearly 1 by reducing the volume fill ratio. This can be realized by either designing a locally varying inner structure, or using slicer settings that change the fill ratio throughout the volume. This tapered structures allow to guide waves within the highly filled sections and allow them to transition gently to the lightly filled regions from which they can be radiated. This type of tapering was used to create a dielectric antenna. Traditionally, multiple layers of different polymers would have to be extruded to guide the waves resulting in reflections between the layers and in a complex production process. Instead a locally varying density of air filled pockets was selected to create a dielectric antenna. Due to the consistency achieved in material production and printing it is possible to predict the antenna performance by simulation.
While the prediction is not perfect it still indicates the success in designing FDM-printable materials that have defined electromagnetic properties.