Radio Frequency (RF) & Wireless Design

Recently I have been asked about 3D printing of fractal antennas and want to share an article on this students approach using a Sierpinski fractal design pyramid antenna :

https://3dprint.com/231977/a-look-at-several-3d-printed-antennas/

For those of you who are unfamiliar with Sierpinski fractal design, here's some context :

https://en.wikipedia.org/wiki/Sierpi%C5%84ski_triangle

I have created my own 3D printed antenna which looks similar to this style of antenna. I called this a "sum of squares" pyramidal antenna, but it is not based upon the Sierpinski fractal design :

Grabcad model

'Stack of Squares' Broadband Inverted Pyramid Antenna

This is a model of a 'Stack of Squares' (4^2 ~ 3^2 ~ 2^2 ~ 1^2) Inverted Pyramid Broadband Antenna that I created custom to see what unique shape antenna I could model that was well suited for 3D printing. This can be printed in a polymer and then sprayed with conductive paint, but is probably be...

In any case the Sierpinski fractal design is a form of broadband antenna similar in performance to a flat horizontal polarized log-periodic antenna :

https://en.wikipedia.org/wiki/Log-periodic_antenna

This article showcases the progression of detail on can go after if there is enough resolution from the printer :

http://www.fractalnature.com/sierpinskitetrahedron.html

One should be aware that these style of antennas typically can not be printed directly from the actual theoretical model since the points of contact are so small and delicate that the 3D printed model will be too fragile. Therefore there must be modifications to the model that allow for manufacturability to ensure the coherency of the material contact points for each pyramid.

There are many ways to do this such as small fillets or adding additional layer thickness to the void areas, but special consideration must be taken into account before starting the 3D printed process.