Although scattering parameters (S-parameters) are widely used in RF and microwave engineering, it seems their adoption isn’t universal in the signal integrity field. I’m hoping this informal survey will air the issues and help us all understand what the barriers (if any) are. Also, please leave a comment if you have opinions not covered in the survey options.
Loading ... Loading ...If you are in the “No” or “Not comfortable” camps, you might be interested in these PDFs on network analysis with S-parameters. They aren’t specific to signal integrity, but are nevertheless useful as a general introduction:
- "Network Analyzer Basics", slides and comprehensive speaker notes from our “Back to Basics” seminar series. Slides 27-29 have a good introduction to S-parameters.
- "S-Parameter Techniques for Faster, More Accurate Network Design", an update of the classic Application Note AN 95-1, Agilent Technologies, PDF slides plus interactive features. Or download a scan of Richard W. Anderson’s original AN 95-1 S-parameter application note.
- Here’s a link to information about the patent pending method that ADS uses to ensure causal, base-delay-causal, and passive time-domain models from S-parameters. Note: USPTO’s web server seems to serve “fragile” links, so if the link is broken, you can try their search page, and searching for application number 20080281893. Also, the patent office page scans are in TIFF format, so you might need to download a browser plugin such as AlternaTIFF to see them.
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The old question of time domain vs. frequency domain. I’ve fought this battle for decades. First in the mainframe computer industry. Each side has proponents and argues for it’s viewpoint. My view is sort of like “which hand would you like to give up?”. Actually I’d prefer to keep both, using either or both when appropriate. Why give up either? Favor either when that one works best.
S params have limitations like finite freq range, limited # of entries, etc…. I use them in both freq and time domain.
“S params have limitations like finite freq range?..”
Can you advise us for a model with unlimited freq. range?
Hi Ike, Thanks for your comment. I added a bullet at the bottom of the post about our method of extrapolating the frequency response in the S-parameter file by 2x to 10x in order to make the time domain response causal.
Hope this helps,
– Colin