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Output power measurement using network analyzer - RF Cafe Forums
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| jabb
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Post subject: Output power measurement using network analyzer
Posted: Fri Jul 07, 2006 2:48 pm
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Joined: Tue Apr 18, 2006
10:40 pm
Posts: 11 |
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hello,
i new to using network analyzer and
doing microwave/RF measurements. i am using Agilent
8364B network analyzer. i did full 2-port caliberation
for power sweep and got s21 vs. Pin curve. now,
i wanted to get Pout vs. Pin curve but the one i
got didn't correspond to s21 data.
i did
an unratioed trace on receiver B (in side the VNA
port 2) to see the absolute output power on receiver
B but instead of showing a curve that is Pin+s21=Pout
it shows me in fact a loss of 10 dB, which doesn't
make sense. i did the full two-port caliberation
so i think caliberation shouldn't be the issue.
do i need to do a receiver caliberation for B. is
that required, though? would i see this bad a Pout
curve if I don't do receiver calibeartion? any help
or feedback will be nice. thanks
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languer |
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Post subject:
Posted: Tue Jul 11, 2006 4:40 pm
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| Captain |
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Joined: Sun May 14, 2006
8:53 pm
Posts: 20
Location: Earth
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I'm not sure if I understand you correctly, but
if I do I think the relative numbers should match.
Meaning you the compression levels for input power
should be the same for both results. I would stick
with the one with S21 since the calibration is fully
accounted for.
For the measurement of "raw"
power into PortB, since the measurement is unratioed
(as you mentioned) the levels have to be checked
for. The VNA has internal attenuators (plus the
couplers) that are automatically accounted for when
you use the VNA "normally". Check the settings and
also check the actual output port power (PortA)
with a Spectrum Analyzer.
But I think you
already found this out:
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am95405 |
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Post subject:
Posted: Tue Aug 29, 2006 6:13 pm
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Joined: Tue Aug 29, 2006
6:10 pm
Posts: 1 |
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You will need to calibrate the "B" receiver in order
to see accurate power levels. What you are trying
to accomplish can be done. Set up a B channel measurement.
Perform a source power calibration on port 1, so
the output power of port 1 is calibrated over your
desired frequency range. Then make a through connection
between ports 1 and 2, and perform a receiver cal
(which is essentially a normalization). Now the
values on the B receiver are accurate. When you
connect your amp, the B will show you the output
power in dBm.
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Posted 11/12/2012
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