collinear dipole antenna

I'm currently studying on the collinear dipole antenna for WLAN at 2.4GHz. I had found one website called wirelessgrumph. It taught the way to construct the antenna but nothing about the theory.
So, does anyone has technical paper or notes about collinear dipole antenna and radial waveguide slot array antenna for WLAN at 2.4GHz?
Thanks very much for your help!

http://www.nodomainname.co.uk/Omnico...4collinear.htm