Here one very interesting antenna - La Fontenna Clone.
It was interesting what is inside FON antenna. On site specs they give it 7dbi or 6.5dbi with 3m low loss coax.
On one Italian blog I found dimensions for building a clone of La Fontenna.
Tere are some interesting result of testing panel antenna for wifi band on Russian site : http://www.lan23.ru/forum/showthread.php?t=1009
Antenna is tested when the pcb print is looking toward to a reflector and back.
You get lower SWR when the pint is looking to a reflector - pictures shows all :
18 or 19dBi - no mater for this one 
. Several dipoles printed on PCB board. Have more dipoles You get more dBis. Will it be 10 12 or 24 - You decide how much do You need.
This is defiantly homemade design. I have one small antenna whit only 4 dipoles - and it works great, so this antenna should work fine. Also will be easy to be rescaled for other bands - 2.4Ghz or 5Ghz only change dimension of the dipoles.
19dbi panel wifi antenna link to picture
Here is the photo from the other side of the pcb board and other part of feeding element
Picture is from this address : diy.wifi-live.pl/node/4 where also have blueprints for less dbi antenna .
On www.zero13wireless.net also has several files posted by sushisan .
Link to files 18dbipcbdipoleantenna.zip
On wireless.com.pt forum I found very interesting article - there are some em simulations of this famous russian antenna. Interesting is that the auhtor made several test with different number of radiating elements.
This is FA20 original design :
Next is with 12 patches :
And finally 16 elements :
Here are results for swr in different simulations :
VSWR 8 Dipoles –> minimum at 2.44ghz 1.46; from 2.4 to 2.5ghz <2.5
VSWR 12 Dipoles –> minimum at 2.45ghz 1.89; from 2.4 to 2.5ghz <2.8
VSWR 16 Dipoles –> minimum at 2.44ghz 1.96; from 2.4 to 2.5ghz <3.4
SWR results are not very good 
This may be due to a different dimensions used by fable to test this design.
He also used very interesting metod to build and test this design. He used aluminium foil and cardboard.
