Hi,
I have build some fractal antennas but had always trouble with feeding. The only one that worked pretty good was the sierpinsky dipole. That worked good, even so the simulations (MWS, HFSS) were not sucessful. However, I also tried the siepinsky triangle to feed like a monopole over ground. The measured results were also much better than sim.
I would suggest that you just build them and measure it. The simulation on fractal antennas were not reliable and hard to understand.
ciao, Bodo
ps: let me know if you know how to feed the sierpinsky carpet