I'm trying to model a lossy transmission line in LTSpice. I want the simulation to work up to about 15GHz and include skin effect and frequency-dependant dielectric constant of pcb traces and material.
I know that in LTSpice it's possible to include Laplace expressions in signal generators. I was hoping that it would work in their lossy transmission, too, but there's nothing in their help files and nothing online.
When I use the simple model statement it works well (along with the appropriate .param statement for R, L, and C:
.model BobLossyTLine3inch LTRA(len=3 R={RperInch} L={LperInch} C={CperInch})
However, when I try to include some type of Laplace expression for resistance or capacitance, I can't find anything that will work. I suspect there's no way to do it.
Has anyone had any success with this?
Thanks.
Bob