Sorry for any inconvenience I might have caused, but upon further
review, I mis-referenced the wrong paper. Although the Wheeler
paper is a "definite-read" to SI engineers, the paper I meant to
TI Effect of Surface Roughness on Eddy Current Losses at
AU Samuel P. Morgan, Jr.
SOURCE Journal of Applied Physics
DATE April, 1949
P.S. If you haven't noticed, my personal library of journal papers
dates back a bit. It's amazing how much of this was done in the
40's & 50's, yet we continue to re-invent the stuff.
On Apr 7, 2:04pm, Pat Zabinski wrote:
> Subject: Re: [SI-LIST] : Q: HSPICE w-elements' RLCGs - conversion coeffici
> Back in 1942, Harold Wheeler went through the analytics to derive
> the equivalent to "lambda" for various forms of surface roughness
> (e.g., rectangular, triangular, etc). In his paper referenced
> below, lambda varies depending up several factors, primarily
> the RMS surface roughness and skin depth (i.e., frequency and
> material properties). He was able to show how lambda could
> reach 2.
> TI Formulas for the Skin Effect
> AU Harold A. Wheeler
> SOURCE Proceedings of the IRE
> DATE September, 1942
> PP 412-424
> Obtaining a copy of this paper would be an excellent start in understanding
> the skin effect on effective resistance.
> Pat Zabinski
> > Another issue... XFX provides an optional fudge factor "lambda" that
> > effectively accounts for copper plane/trace surface roughness. This fudge
> > factor effectively scales the default copper resistivity in the skin layer.
> > The default value of "lambda" is 1.
> > Has anyone of you done any study as to what this Lambda should be? How does
> > this value vary (if at all) from one board vendor to another ? Is there any
> > particular value for Lambda if one is going to use XFX' data with Hspice
> > W-elements?
> Pat Zabinski ph: 507-284-5936
> Mayo Foundation fx: 507-284-9171
> 200 First Street SW email@example.com
> Rochester, MN 55905 www.mayo.edu/sppdg/sppdg_home_page.html
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>-- End of excerpt from Pat Zabinski
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