This parabolic reflector antenna, made with cardboard and foil, can increase your wireless reception by 6dB. The performance of this reflector is comparable many commercially produced antennas.

How to make:

1. Download Template or another reflector template design : parabolreflector_en.pdf
2. Open in a graphic app and resize as desired.  Ensure that you keep the square on the diagram square.
3. Print image on business card stock or acetate (document protector).
4. Cut it out and open the six slots with scissors or an X-Acto knife.
5. Glue tin foil to either side of the reflector surface (its best to bend the surface first as foil doesn't stretch well!)
6. Assemble by placing the six tabs in the six slots.

Note:  If printed at the download size you will see about 9 dBi of gain.  If you double the size of the image before you print it you will see about 12 dBi of gain.  If you place two reflectors on an AP with two antennas you will see an additional increase in performance

Six inch reflector pattern at 2.4 GHz:

Source: https://www.freeantennas.com/projects/template2/index.html