Hi, Balaguru thavamani. I am not quite sure which version of IE3D you are using. My IE3D version is 11, and the chapter 9 is "Lumped element extraction and signal integrity". It does include the "Finding transmission line characteristic" and I have already followed the introduction to get the characteristic impedance of the differential broad-side coupled stripline with RF ground.
The problem is that when I use the derived stripline with 50Ohm/70Ohm/100Ohm to build a quarter-wavelength transformer, the results is not stable.
When the feeding 50Ohm/100Ohm line is pretty short, the performance of the 1/4 transformer is OK, but when I made the feeding linea longer, the magnitude of the S-parameters are different.
But according to the microwave network theory, if the characteristic impedance of the feeding transmission line is uniform, it is equivalent to add exp(j*bete*l) to the S-parameters, so the magnitude of the S-parameters should be the same.
So I am wondering whether the "find transmission parameters" function in IE3D has some limitation, or the differential setting of the "advanced extent" ports has some limitation", or physically in such high frequency, the higer-order modes are excited and the microwave network theory cannot be applied.
Thanks.