Also, call me a conspiracist, but...

I am always suspicious of on-line filter calculators, as a possible means of intelligence gathering. If you work at Boeing, Lockheed, NG, Raytheon, etc. I would expect that a lot of those sites are blocked.

http://tonnesoftware.com/ also has some nice freeware. One problem is that parasitics of lumped elements are not taken into account in any freeware I have seen.
Steve

That is an interesting network, is it published somewhere? I don't know HFSS well enough to help with that, but maybe you need to consider how far the cables are from ground. The outer jacket of one of the cables will be hot with RF energy, allowing it to be close to ground may change the result do you have a 3D image we can look at?

Steve

I did some checking around. That firm seems to have disappeared without a trace. If anyone knows if there is another company picking up the product line please let us know and we can add it to where-are-they-now.

A guy I knew long ago used to say "chicken today, feather pillow tomorrow". Maybe we can identify this particular pillow!

Steve