DIY WiFi Antennas

Rob Flickenger

Hacker Friendly Publishing

1/4 wavelength ground plane

• Very easy to make
• Tiny!
• Approximately 2 to 4 dBi gain
• Useful for testing or indoor use

Collinear omni

Collinear omni construction

• Simple to build
• Weatherproof with PVC pipe
• Approximately 7 to 9 dBi gain

Biquad

Biquad used as dish feed

• More complex design
• Can be tricky to build correctly, depending on available materials
• Versatile, with impressive gain in a small space
• About 11 dBi gain alone
• 27 to 31 dBi gain when used with a dish!

http://trevormarshall.com/biquad.htm

Slotted waveguide

http://trevormarshall.com/waveguides.htm

Very large parabolic

http://www.wifi-shootout.com/

Pringles Can: In use

Pringles Can: Detail

Pringles Can: Dissected

Pringles Can: Small version

Pringles Can: One wavelength

Problems with the Pringles Can

There are a number of practical problems with the Pringles can design.

• Cardboard can is not waterproof
• Antenna is very fragile
• Design is complex and prone to error
• Can dimensions are inappropriate for 2.4 GHz

Home-brew antenna shootout

http://www.turnpoint.net/wireless/has.html

Ideal can for 2.4 GHz

Stew can

Cookie can

Use what you can find

Can as dish feed

• Possibly the simplest antenna design, assuming you can find an appropriate can
• Construction is very easy
• 10 to 14 dBi gain is typical, with approximately 60 degree beam width
• 30+ dBi gain is achievable when used as a feed for a parabolic dish

Credits

Portions of this talk were adapted from Wireless Networking in the Developing World, http://wndw.net/