aaron_do
|
Hi RFICDUDE,
I think for differential circuits, a differential port needs to be represented by two ports, one for the positive terminal and one for the negative, and each one referenced to ground.
The question is then, where is the ground reference in your EM model? In the schematic simulation, all reference ports would be tied to the same point, so ideally in your EM model, you also need to make sure all ports are referenced to the same point. Since this doesn't seem to be possible, the next best thing is to have all ports referenced to an ideal ground plane (low resistance and inductance). However, my problem is that if your circuit doesn't have an ideal ground plane (i.e. its not real), then there might be problems. For example, some of the return current might flow through your ideal ground plane instead of the real return path.
So basically I'm still wondering what is the most accurate approach to EM modeling...
OK I realise it might be difficult to follow my thinking, so if its unintelligible, please let me know and I'll try and draw some figures.
thanks, Aaron
|