lna measurements
I have implemented a LNA using Sirenza's SBB-5089 MMIC on FR4 board. I have access to a network analyzer in the University lab containing HP 5071 network analyzer. I wnat to measure the LNAs noise figure using ONLY network analyzer. Is it possible?
Thanks
I don't think so.
VNA is used to small signal response of circuits. It uses a sweeped CW signal and detectors to evaluate S parameters.
Noise figure is measured with a good accuracy with a noise source and Y-factor method, so you will need a receiver (typically a spectrum analizer or a dedicated instrument) to do it.
I hope it can help.
Mazz
some VANs of anrtisu have noise figure measuetns ,
but if u want to measure the NF use NF meter of agilent
so ur VNA is not enough
khouly
what is the price of NF meter( from several vendors)?
check
http://www.home.agilent.com/agilent/...0&cc=US&lc=eng
khouly
SBB-5089 MMIC have high NF ,it is not good for LNA.Use SPF-5043Z with NF=0.8dB and freq=100-4000MhZ,in/out 50 ohm matched!
It is 28KS! Is there any low cost NF Meter (about 5KS)?
5 K Noise figure meter , i doubt it
u can search for used items , but new one , it will be hard
khouly
Thanks for all replies.
I will now search for a cheap NF meter.
Thanks
If you have a good spectrum analyzer, you can "build" your own NF meter buying only the noise source and a low noise preamplifier.
As NF meter uses the Y factor method, based on high temp/low temp noise source, you can manually measure it (or implement a software in Labview, for example).
See agilent application notes for details, if interested.
Mazz
The answer is NO, IT'S NOT POSSIBLE.
but...if yuo have avaliable a noise generator
if your VNA may be switched in receiver mode
if your LNA has enough gain to mask the noise of VNA
the manual switching, noise measurement may be tryed, but this is a thinking speculation.
In any case, when measuring NF , the causes and sources of uncertainty are almost infinite.
My suggestion is if you have not a NFA and You cannot buy, the most cheaper way is to loan it for the period You plan to use.
of course u can do it, with the newest high performance Agilent VNA:PNA-X,
u can finish all the LNA measurements including the NF, IMD, harmonics,Gain
compression.
pls check www.agilent.com/find/pnax
Spectrum analyzer can measure LNA noise figure!
you can measure the NF with a network.
1. connect the network for a S21 test.
2. connect the LNAs output to port 2.
3. meaure the noise level.
4. connect the LNA to DC.
5. measure the noise rise, it's G+NF, you know G so you can deduce NF.
6. if you don't see a noise rise it's becuse the network has a high NF, if that's the case connect a reference LNA between your DUT and the port.
you should also use a low RBW.
enjoy