Pictures are from this site starhill.org
Interesting design as You can see.
There are four stacked biquads or bicircles over a corner reflector.
Here is a PDF file whit a dimensions of this wifi antenna : 12dB_sektor_antena.pdf
Interesting moments are grounding and feeding of the circle elements – you can see this here :
I never sow biquads to be grounded or feeded like this.