Interesting post in zero wireless forum about stacking four atmos antennas.
The result looks very bizarre really :
here is the link :
http://www.zero13wireless.net/foro/showpost.php?p=21206&postcount=110
At las time a lot of hits came from a Poland there are some good wifi forums but I cant find online translator 
Here one interesting antenna from diy.wifi-live.pl
This is some strange Biquad and Yagi hybrid.
Dimensions :
/odległości:
deflektor- 36
/19
quad- 34
/17
direktor1 33
/17
direktor2 32
/17
direktor3 31
/17
direktor4 30
/17
direktor5 29
There are no results or testing for this antenna.
Here is the scans of inside - very thin pcb board is used.
Some time ago I needed some 5ghz antennas - this is the first thing that I bought.
Dual-band 11a/g 7/5dBi Indoor Omni Antenna from trendnet.
The papers says :
| Frequency Range | 802.11a: 4.9 ~ 5.875GHz 802.11b/g: 2.4 ~ 2.5GHz |
| Gain | 802.11a:7dBi 802.11b/g:5dBi |
| VSWR | 2.0:1 |
| Polarization | Linear, vertical |
| HPBW/ Horizontal | 360° |
| HPBW/ Vertical | 802.11a:25° 802.11b/g: 35° |
The stupid thing is that on the site specification and in pdf data sheets was said that this antenna have VERTICAL polarization, but now I can see that omnidirectional pattern came whit horizontal polarization!
This may be the reason why I am not happy whit this wifi antenna and it is still laying on my desk.
I will test it again when I have some time.
The other small wifi antenna that I have from trendnet is working great - I have small 5ghz link whit it - these days maybe will scan ti too.
I don’t like Yagi antennas /sorry/, and I never try to make one , but this look interesting - it is only one side pcb design that differ from the most dual sided similar.
On the side is said that this antenna is a clone to a commercial one, but not a name or model is mentioned.
The dual sided board is needed to make the feeding point of the yagi antenna - here we have something very interesting and different to be able to make all needed parts on one sided PCB board. In fact this is dipole.
Link to the page : http://www.aribg.it/Tech/WiFi/Yagy24ydm/yagi24ghz.htm
Here is schematic :
Here some pictures whit dimensions :
On the second picture You can see haw to assemble the dipole - this is the interesting part. This antenna is feeded by dipole not whit loop like most Yagi antennas. Here they make a balun whit the stripped coax and the pcb board.
There is also one aluminum disk used to hold the board that is used as reflector :
On the site is said that this antenna have 11.5dB gain. And for last there is a SWR test for this antenna pretty good results I thing :
The peek is little out of wifi band but we still may get very good results for wlan applications.