Home-Brew Antennae
Omnidirectional Antennae
Make your own: Guide
Directional Antennae
Cantenna
Make your own: Extremetech guide on building a cantenna
File:Circular waveguide optimise.xls
Sectoral Antenna
Turn an Omni into a Sector
The designs shown for a reflector can be applied to a standard omni and will turn the omni into a sectoral antenna.
Taken from: Freeantennas.com