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Simulators >> RF Simulators >> front-end matching noise contributed by itself
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Message started by baohulu on Sep 22^nd, 2011, 9:40pm

Title: front-end matching noise contributed by itself
Post by baohulu on Sep 22^nd, 2011, 9:40pm

hi all,
during matching between antenna and LNA, what software do you use?
I use a software called smith-chart, it can do matching in smith chart, however, it can't give a noise and gain simulation. Is there any software can do both?
besides, when we do front-end matching, how can we considering noise contributed by the parasitic res of L and C? during the matching, at one hand, it needs satisfy matching requirement, at the other, it should introduce as low noise as possible. I have troubles about how to balance both.
for example, in a T type matching, which is L-L-L connected. the three L all assumed to have Q of 20 in operating frequency, then how can be choose the suitable value of each L to do matching and at the same time reduce total noise contributed by the three L?

have you ever considering this?

Title: Re: front-end matching noise contributed by itself
Post by RFICDUDE on Sep 23^rd, 2011, 4:43pm

In general the things you need to watch out for are

1. Keep the equivalent series resistance low for matching components connected in series.

2. Keep the equivalent shunt resistance high for matching components connected in shunt.

By "equivalent resistance" I mean the measured real part of the series resistance or the real part of the conductance for shunt components measured at the frequency of interest.

Topology of the matching network can also make subtle but significant differences in NF when dealing with components with varying Q factor.

The following is a good article on the topic

Analyze Matching Networks For Low-Noise Amplifiers
Vladimir Aparin | ED Online ID #15569 | May 2007
Microwaves and RF

Title: Re: front-end matching noise contributed by itself
Post by baohulu on Sep 25^th, 2011, 7:12pm

hi, RFICDUDE
can you attach the paper? I can't find it.

thanks

Title: Re: front-end matching noise contributed by itself
Post by RFICDUDE on Sep 26^th, 2011, 5:55pm

Here is the link the the Microwaves and RF article.

http://mwrf.com/Articles/ArticleID/15569/15569.html