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icguy

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how to simulate noise matching for LNA in spectre?
Mar 11^th, 2008, 7:39am

HI:
I can simulate the equivalent noise impedance in ADS to obtain the difference between the noise impedance and the optimal noise impedance,which is a very useful function.But in spectre, i only find the simulation-NF and NFmin.I don't know which component and how much to adjust to reduce the NF.

Hope to get explanation soon Cheesy

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pancho_hideboo Senior Fellow Offline Posts: 1424 Real Homeless	Re: how to simulate noise matching for LNA in spec Reply #1 - Mar 11^th, 2008, 7:58am GammaOpt is available. If my memory is correct, this is defined as variable of Gmin.
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icguy

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Posts: 8
Seoul Korea

Re: how to simulate noise matching for LNA in spec
Reply #2 - Mar 11^th, 2008, 6:48pm

As i know, Gamma is relative with channel length.I have simulate Gamma through Common-gate LNA whose Noise Factor is 1+Gamma.The simulate results is approximately from 0.7 to 0.9,not more than 1,which is very similar with the theory in short channel.

Sorry,I don't understand what is your meaning,Could you just explain that again in detail,thx.

I want to obtain the equivalent noise impedance Zopt through SpectreRF.

I am looking forward to a favorable reply at your earliest convenience.
My eamil: icguy@yahoo.cn

Reference:

T.K.Nguyen, C.H.Kim,G. J. Ihm,M. S.Yang, and S. G. Lee, �CMOS
low-noise ampliﬁer design optimization tehcniques,� IEEE Trans. Mi-
crow. Theory Tech., vol. 52, no. 5, pp. 1433�1442, May 2004.

pancho_hideboo wrote on Mar 11^th, 2008, 7:58am:

GammaOpt is available.
If my memory is correct, this is defined as variable of Gmin.

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pancho_hideboo

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Re: how to simulate noise matching for LNA in spec
Reply #3 - Mar 11^th, 2008, 10:51pm

You are misunderstanding.

"Gamma" I mean is reflection coefficient.
So maybe "GammaOpt" is refered as "Sopt" in Agilent ADS.

See attached figure.
In cadence, "GammaOpt" is available as "Gmin" in direct plot menu.
In results browser, this is defined as Yopt("Gopt" and "Bopt") alternatively.

Yopt is the source admittance that gives the minimal noise factor Fmin (corresponding to the source reflection coefficient Gamma opt)
and Rn is the equivalent noise resistance. Finally, NFmin, the minimum noise figure, is Fmin, the minimum noise factor, in dB.

See pp.1560-1561 of $CDS_INST_DIR/doc/spectreRF/spectreRF.pdf

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cds_sp_noise.jpg

« Last Edit: Mar 12^th, 2008, 7:50am by pancho_hideboo »

Kita━━━━━━(ﾟ∀ﾟ)━━━━━━ !!!!!
http://www7.plala.or.jp/ungeromeppa/flash/kita.html
http://www.youtube.com/watch?v=mjIxGh55bMM&feature=related

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pancho_hideboo Senior Fellow Offline Posts: 1424 Real Homeless	Re: how to simulate noise matching for LNA in spec Reply #4 - Mar 11^th, 2008, 10:52pm This is ADS output data for SP analysis.
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icguy New Member Offline Posts: 8 Seoul Korea	Re: how to simulate noise matching for LNA in spec Reply #5 - Mar 12^th, 2008, 1:44am Thank you very much! Please accept my thanks for your support. By the way,my"SpectreRF User Guide" is Product Version 5.0 published in September 2003. Could you send the lastest version to me? I cann�t express my excitement and my gratitude much more!
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pancho_hideboo Senior Fellow Offline Posts: 1424 Real Homeless	Re: how to simulate noise matching for LNA in spec Reply #6 - Mar 12^th, 2008, 2:04am I can't distribute product manual freely. And you can find necessary information in your "SpectreRF User Guide" of Product Version 5.0 published in September 2003.
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icguy New Member Offline Posts: 8 Seoul Korea	Re: how to simulate noise matching for LNA in spec Reply #7 - Mar 12^th, 2008, 5:26pm Thank you all the same
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