GSG excitation in EM simulator

Hello,

I know GSG excitation is really complex in HFSS. It is necessary to make a pec bridge as shown in: http://orbit.dtu.dk/en/publications/...37023771).html
And after, we have to deembbed this bridge for more accuracy.
Another solution, not to change the structure adding a bridge, would be to use 2 lumped ports, one for GS, another for SG, and combine them in pos-simulation to make one port. It is simple.
But in HFSS for example, the analysis is made exciting all ports sequentially to compute at the end S-parameters. In this case, when GS port is excited for example, the other ground side is not grounded, as it is connected to signal path by a terminal (a resistor). I think that it can produce inaccurate results. It exists an option "Composite excitation" to excite all ports at the same time. But, using this option, S-parameters are not calculated.
If it would be possible to excite GS and SG ports at the same time during EM calculation, we could ensure that both sides are grounded at the same time.

Anyone, know if any EM simulator can do that? CST, Sonnet, ... ?

Thanks,
Emmanuel

I have used Sonnet and Momentum with composite ports (-)(+)(-) for GSG.
6 pins -> 2 ports