Harold,
For a typical uniform transmission line, depending on the length and size
of the interconnect, there is a region in Impedance vs Frequency plot where
impedance is pretty much determined by sqrt(r/jwc). This is called the RC
region. After that region, the impedance pretty much constantly remains
100Ohms let's say as example. WAG here, but maybe if you can find the
transition region and force a constant value for the RC region, this can
help you achieve what you're looking for.
Just to throw this in here, please beware that TDR itself has a lot of
quirks. As you go further and further down the line, your accuracy pretty
much goes to crap.
Interesting thought though.
-Ryan
On Wed, Jul 6, 2016 at 4:22 PM, Harold Wang <haroldw@xxxxxxxxxx> wrote:
Hi Experts,
When performing TDR simulation using S-parameteres, we know that the final
steady-state impedance (Zfinal) is equivalent to the DC impedance of the
DUT and the initial impedance (Zinit, t=0) is represented by the impedance
at the highest recorded frequency in the S-parameter data.
When doing a TDR on an uniform lossy transmission line, we expect the
impedance plot to raise from Zinit to Zfinal due to resistive loss in the
transmission line. Can we predict the slope of this rise? For instance, if
I moved 50ps into this uniform lossy transmission line, what is the
impedance rise that I should expect? What frequency point does that map to
in the S-parameter data?
The end goal is to separate the natural rise of an uniform lossy
transmission line from true impedance increase due to structural change.
Thanks,
Harold
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
