CST Simultaneous Excitation

Hey guys,

I need to simultaneously excite 3 ports with different excitation signals. I am doing this by selecting the excitation signal in the simulation module (shown in Figure 1 attached). I am having trouble with the simulation results. The S-parameters obtained from the simulation do not make any sense (Figure2). Can someone please tell me if this is the right method for excitation or not?
I do not get any problems with the S-parameters when I excite all ports with the same excitation signal (Figure3). For this case i dont use simultaneous excitation. I just set a signal as reference signal and simulate. How come the simulation results dont make any sense when simultaneous excitation is used? any help would be much appreciated.

How can you know?

You have magnitude only s-parameters, phase is unknown. Thus you can't predict if superimposing signals at multiple input ports will increase or decrease the magnitude at a certain frequency.

Presumed you are modelling a linear system (e.g an antenna array), the result with simultaneous excitation can be predicted from the complete (magnitude and phase) set of s parameters.

Thanks for the reply FvM. The S-parameters obtained from the simulation (figure 2) dont make sense to me because of the labelled notation. CST usually provide both the reflection coefficients and coupling parameters in the S-parameters folder. you can see this in figure 3. but for some reason when I try to simultaneously excite ports I only get 3 signals in the S-parameters folder instead of the expected 9 signals (like figure 3).
so what im trying to understand is what exactly does the "simulataneous excitation" option in CST do and also what the labelling in figure 2 means (S11? S21?)
Again any help is much appreciated! thanks