Re: [SI-LIST] : Transmission Line Conductors

HANS_MELLBERG@NON-HP-Cupertino-om5.om.hp.com
Thu, 18 Sep 97 16:07:55 -0700

As far as the permeability is concerned, you can safely assume a value
of 1.0 for the mu-sub-r. If you are using nickel, iron or cobalt as
your conductor material or part of your alloy,then you need to worry
about a non-unity value. The conductivity (real value) all it does is
generate ohmic loss. The value you need to concern with is the
frequency dependant skin effect wich essentially increases the ohmic
resistance with frequency (R-sub-s).
So, to answer you question, changing the material down the conductor
path will essentially be insignificant except for ohmic losses. The
impedance will stay the same (assuming the diameter is unchanged)
Hans Mellberg

______________________________ Reply Separator _________________________________
Subject: [SI-LIST] : Transmission Line Conductors
Author: Non-HP-AHardie (AHardie@compuserve.com) at HP-ColSprings,mimegw5
Date: 9/18/97 3:19 PM

All the transmission line impedance formulae that I can find do not take
into account the
conductor's properties such as conductivity and frequency dependant
permeability (mu).
Does anyone know how a change in transmission line material part of the way
along it's length
affects the transmission line's performance?

Alastair Hardie.