Home-Brew Antennae
Omnidirectional Antennae
Make your own: Guide
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
Cantenna
Make your own: Extremetech guide on building a cantenna
File:Circular waveguide optimise.xls