Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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My Hobby Website:
Loadpull in ADS - 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.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: Loadpull in ADS Posted: Sat Dec 31, 2005 12:54
Does any one have experience with the many loadpull templates
in ADS. I just want to know what exactly is s11_rho and s11_center and
how do you modify its default setting for your own simulation?? The
default is s11_rho = .75 and s11_center = 0.0 + j*0.0.
in the same templates the S1P_Eqn component has the value for its parameter
S[1,1]=LoadTuner. What's this 'LoadTuner'? I mean when you type this
in what is ADS reading/doing?? Thanks
Post subject: Posted: Mon Jan 02, 2006 1:47 am
Here is a pic of a Loadpull simulation of simple PA. Below shows
the power contours. I am very new to this I don't have a whole lot of
experience so please tell me if these contours remotely look right?
The reason for my suspicion is that in ALL of the references I have
seen in textbooks and other places all of the power contours are, unlike
mine, to the left of the smith chart...mine are to the right and open
the like "(" instead of opening the other way like in references ")".
The reference system impedance is 50 as usual. Also, I am expecting
the optimal load ipmedance to be actually higher than 50 Ohms since
my output power requirement is very low (10 dBm). This question sounds
really dumb but what can i do? that's the best way for me to ask to
clarify my confusion. Anyone knows a reference/tutorial that talks about
loadpull/power contours in simple terms....not too high level. Thanks
Posted: Mon Jan 02, 2006 11:27 am
You are coorect in your assumption
about the load pull being to the left. Power amplifiers are normally
comprised of fairly large devices and as result the impedance looking
into the output is relatively low, hence the contors show to the left
of the smith chart. Now, some devices are internally matched, therefore
, what you may be looking at is a matched device. Cant say for sure
since I donot what device isbeing plotted. Steve Cripps has written
many books on power amplifier design, also, you may wat to google PA,
or Load PUll to find other relative references.