How to 3-D print your own invisibility cloak

Engineers have designed a plastic disk that uses microwave light to make objects in its center disappear


Now you see it…

The invisibility cloak Harry Potter brandishes against dark lords and nosy professors is now a reality-at least in microwave light. Duke University engineer Yaroslav Urzhumov has designed a plastic disk that makes a small object placed in its hollow center invisible to frequencies from 9.7 to 10.1 GHz (close to the range used by radar speed guns). Holes in the doughnut-shaped cloak can eliminate an object’s shadow and decrease its ability to scatter light. In effect, the cloak guides the microwave beams around the object so they can’t bounce back-rendering it invisible. Until scientists can scale up, however, it might be useful only for getting toy cars out of a speeding ticket.

Time: 3 to 8 hours

Cost: About $100

Difficulty: 1 out of 5


  1. Find a 3-D printer, preferably one that builds objects in thin layers of plastic (a process called fused deposition modeling). If you don’t own a 3-D printer, can’t borrow one, or lack the funds to buy one-typically $500 or more-you can pay an online company (such as Shapeways or RedEye on Demand) to print a design for you.
  2. Download Urzhumov’s design file at here and print it out. (The default thickness is 1 centimeter, but it can expand as tall as a 3-D printer allows.)
  3. To use the invisibility cloak, line the disk’s inner ring with aluminum foil, lay it on a flat surface, and put an object 5.4 inches long or less inside. Any microwaves shining on the disk’s outer edge won’t reveal your precious property.

Before accessing Urzhumov’s 3-D-printing file, please note: Urzhumov and his colleagues retain the copyright to the work, and by downloading this file you agree: 1) to take full responsibility for the consequences of using it; and 2) to indemnify Duke university and all individuals involved in the creation of this work of art-as well as Popular Science and its parent company, Bonnier Corp.-from any and all claims of damage against them. (That said, you can download the file here.)

This article originally appeared in the September 2013 issue of Popular Science.