These anlayse work at 2.5GHz in FR4 type PCB material for those of us who want to drive ?? or an antenna = Bluetooth, Wifi, zigbee, or GPS antenna module and want to see how much a 'longer than desirable coax' run detriorates the NF of the Receiver. The skin effect is in there, but I did NOT want to make this a 'broadband model' Skin effect issimply at 2.5GHz. Boradband Model is reserved for TUTORIAL - Example 3 analyzing a twisted pair.
It's only 19kB in zip. Contains the Explanation, femm 'step=by=step' and the LTspice final models, [you have to do yur own PSpice from them.]