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
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Two peak curve on S22 when measure return loss - 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: Two peak curve on S22 when measure return loss
Posted: Sun Apr 23, 2006 10:33 pm
Sun Apr 09, 2006 8:48 pm
currently, i doing PA evaluation board measurement.
i just wanna to know why on the return loss of S22 have 2 peak curve
occur? is it because there have 2 resonane circuit on the board? if
yes, where is that 2 resonance circuit forming on the board?
(on output of this board's circuit diagram, there have 2 capacitor placed
in parallel.(one is act as DC bolck and another one is short to ground.).
And so have some capacitive decoupling circuit)
Post subject: Posted: Tue Jun 13,
2006 10:50 pm
Joined: Tue Mar 15, 2005 11:43
I am not very
sure about your question. But I assumed that it's kinda valley on yout
S22 measurement. First, the S22 will go much lower at your operating
frequency which means it has the best return loss in the operating frequency.
Regarding 2nd valleys appearance, I guess it most likely the
resonance frequency appears. It can be caused by the capacitive coupling
somewhere in the circuit. I am not very sure about this either. Please
feel free to correct me if I'm wrong.
Post subject: Posted: Wed Jun 14, 2006
Joined: Tue Apr 11, 2006 8:13 pm
Is your PA enclosed in a metal housing? Could there be