Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
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design engineer. The World Wide Web (Internet) was largely an unknown entity at
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Thevenin and S parameters - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
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Post subject: Thevenin and S parameters... Posted: Fri Jan
26, 2007 11:18 am
Joined: Fri Jan 19, 2007 10:36
I'm have “little” doubt about s-parameter
simulations . My question is very simple but I do not know if the answer
is the same .
The Thevenin theorem can be applied to a s-parameter
That is, if I do a simulation using a port P1 with 50
ohm where at valley of the port I've connected 2 impedences, one in
parallel Z1 and one in series Z2. Supposing I obtained S11 at frequency
f1. Then, if I incorporate the impedence Z2 (at frequency f1) in the
port 1 impedence (using Thevenin), can I obtain the same S11 parameters
for f1 fequency?
Posted: Fri Jan 26, 2007 3:18 pm
Mon Jun 27, 2005 2:02 pm
In S-parameters you can short voltage sources, but you can't create
an open circuit which is required to create the equivalent resistance
for Thevenin. You can only connect the network characteristic impedance
to derive each of the S-parmaters.
Hence Thevenin theorem applies
only at DC and low frequency networks where it is possible to use open-circuit,
but not to RF/Microwave networks.