semi-rigid coax transformer

Does anyone have experience modeling baluns or transformers which have ferrites through them (for lower frequency coupling)? I'm trying to simulate a 30-512MHz PA but it uses these parts. I temperature and power are large factors in these models.

http://www.polyfet.com/HFE0503_Leong.pdf
Here you go.
Greets
Jens

Wow, isn't this ironic....

Thanks!

Polyfets designs seem to work really well.
I built the TB-207 and it almost works flawlessly to spec.(200MHz-1GHz)
The amplifier from the link simulates really well.
Tried in ADS. You can download the ADS files from Polfets site.

Greets