#### Humberto Riveiro

##### Newbie level 3

This is my first post.

I wanted to know what are the real applications of modeling (or extracting) s-parameters from a transmission line using the telegraph equations and its characteristic impedance.

I saw a few papers, all of them talk about measure the s-parameters using reflectometers and then use that parameters for describe the device under test (Transmission line for example).

My question is, if people know the material and the geometry of that device, why they don´t model mathematically the s-parameters instead of measure them?

I understand that some devices are dificult to model because of its geometry. This is the only reason?

Thanks in advance

Humberto