Hello,

As far as I've checked, coax cable models in PSpice (TLine.lib library file, which could be open in any ASCII editor) have some definition which looks strange for me. At least, I don't understand where it came from. For example, for RG58C/U coax cable, for its both .model and .subckt options the model series resistance is defined as "r={63.9098u*sqrt(2*s)}". This resistance is intended to model the skin effect losses, which is proportional to sqrt(s).

Later on in the model we can find the commented line with following "r={63.9098u*sqrt(PI2*frq)}". Here it is proportional to sqrt(2*pi*freq), which is a sqrt(s).

Exactly the same file exists in the pre-ORCAD version - MSim.

My question is why it is proportional to sqrt(2*s) in the active model and not to sqrt(s)? Where this factor 2 came from - mathematically / physically?

Sincerely

Pavel