directional quasi yagi

How would you go about making a quasi yagi directional is it simply a matter of increasing the number of directors at the distance relative to a normal yagi?

if i use this
http://www.dur.ac.uk/comms.systems/p...asi%20yagi.pdf

and than add more directors at a 1/2 wave lenght will that work?

i am trying to make a 2.4ghz directional antenna size is important the gain is not important at all as long as it can go 30 meters.