I went on web to find impedance calculator for asymmetric stripline. Basically I got two different answers.
I have asy stackup of H1=8mil, H2=25mil, all 1oz copper(1.4mil). I set width of trace of 8 mil with er=3.55. At least two calculators gave 67ohm, two gave 56ohm. What is the story?
Below are two links, first gave 67, the second gave 56. Which one should I trust?
If you are able to verify these values with a EM simulator, check them ..
They give really different values ( there may be a computation method differences )