[SI-LIST] Time Domain Simulation with Limited Frequency Range S-parameter data
- From: Harold Wang <zidaneharoldwang@xxxxxxxxxxx>
- To: "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Mon, 16 Feb 2015 18:46:47 +0000
Hi All,
I am trying to figure out what is the optimal approach to get the most accurate
time domain simulation result from an limited frequency range S-parameter data
Let's take a simple stripline trace as an example. The maximum frequency in my
application is 13GHz, I have S-parameter simulation data up to 40GHz. The S11
data is shown below:
If I do a direct IFFT on the data above, the time domain result looks rather
discrete and nonphysical (the DUT starts from 125ps to 300ps). Could someone
help to explain why this is the case here? Is it because the sharp cut off at
the S11 data at 40GHz?
After applying hanning window to the S-parameter data, the S11 and TDR plots is
shown below. The TDR plot is what I was expecting: you get a some port mismatch
at the attach, shown as the overshoot at 50ps and 175ps. Between 75 and 150ps
is the real trace impedance and the value agrees with other simulation tool as
well.
The part that puzzles me is that we damped the high frequency response of the
original S-parameter data to achieve this. If we don't care about the higher
frequency (>fMax) response, why is it always recommended to simulate beyond
fMax and filter it afterwards? If we do need to see the "full picture" but need
to damp the S-parameter, how do we determine the correct amount of filtering
needed?
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
Other related posts:
