'Stack of Squares' Broadband Inverted Pyramid Antenna

Last crawled date: 1 year, 10 months ago

This is a model of a 'Stack of Squares' (4^2 ~ 3^2 ~ 2^2 ~ 1^2) Inverted Pyramid Broadband Antenna that I invented 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 better off 3D printed in metal and then sintered for hardness.

This antenna is similar to the Sierpinski Fractal style of antenna, but is not based upon fractals, but merely squaring functions. The overall geometry is the longest wavelength and each successive lower tier represents a shorter wavelength (higher frequency). However the largest and smallest will dominate. Here's a good whitepaper on the subject : https://repository.wit.ie/3299/1/Design%20of%20Microwave%20Components%20using%20Direct%20Metal%20Laser%20Sintering.pdf

The circular enclosure is simply a method to keep the pyramid upright and level against the sides of the orange clear acrylic and flat across the top. The center conductor is soldered (not shown) with the base being a 2.54 mm or 0.1" thick piece of copper plate to serve as a ground plane. This is important to prevent coupling of the antenna onto the outside of the coax. I have also extruded the bases upward 0.5mm to merge with the intercepting points since the points touching each other would be too delicate to manufacture. Perhaps I could have fileted these but merging with an extrusion was easier at the time.

Overall dimensions of the top is 60mm x 60mm, so each pyramid is 15mm x 15mm. Overall height is 60mm, so each pyramid is 15mm tall. Diagonal corner edges are SQRT((60mm)^2 * (42.4264mm)^2) = 73.4847 mm = 7.35 cm which is about 1.02 GHz.

The smallest pyramids and inverted apertures are 15mm and are tuned to 4 times the frequency, so should be in the 4 GHz range. Also the triangular cutouts serve both as capture areas as well as image areas.

I hope to perform a 3D electromagnetic simulation and will post later the results. If anyone out there wants to take the initiative, then please let me know of your results. Thanks !