I will summarize my thoughts to make sure I understand your point. If I have an EM model for a transmission line, testbench 1, 2, and 3 are both correct because schematic ports are effectively floating. testbench 1 and 3 are equivalent because they have reference pins connected to GND. Testbench 2 has a floating reference pin but as you mentioned above, there will be no difference between the results of 3 testbenches (1,2,3).all your schematic ports are effectively floating w.r.t. the substrate backside
schematic Term have their refence node at some EM model pin/port, and do *NOT* connect to schematic GND.
Is that testbench (4) VALID for measurement case?
No, this two port measurement is valid, because it implements what I described in the second paragraph above.So can I say that the measurement result of a transmission line is not valid?
In an ideal world, it would be sufficient to model a differential port at the two wires, but in real world with curves and bends there will be some mode conversion to common mode. I have seen funny resonances in results if such common mode conversion happens, and the common mode is not terminated. So my modelling approach in that case are two ports on each end, with their reference pin(s)on the ground polygon(s), so that both differential model and common mode are supported.but what about a differential one?
Setup 2according to you which setup would be valid?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?