I was looking for an antenna manufacturer, too, but unfortunately the one I had in mind
does not have a capability to handle that fine material as it is used for 1090MHz.
Look on the development page in order to see what I've used for that,
and also F5ANN describes some antennas for Mode-S receptions,
they all have been rebuilt several times with success.
Maybe there is another one who could provide the community with good and reasonably priced
Mode-S antennas and not just myrical promising ones for a horrible price.
From the current knowledge, the Mode-S Beast works with any kind of antenna that is designed for 1090MHz.