New breed of transponder antennas

Hello all,

I see a new type of transponder antennas on the market, for example the
Filser DP1090-5:
http://glider-equipment.nl/catalog/p...a-dp10905-p-63
These seem almost too good to be true; Low cost & complexity, easy
installation inside (non-carbon) fuselages..
Does anyone have experience with these antennas. Performance? Compatibility
with transponder models commonly used in gliders? Examples of EASA approved
installations?

Thanks,
Lars Peder (who finds that more and more of the airspace around him becomes
class C :-( )