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Design >> RF Design >> Process_corners
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Message started by gaurav vaidya on Apr 16^th, 2012, 10:11am

Title: Process_corners
Post by gaurav vaidya on Apr 16^th, 2012, 10:11am

hello everyone i have designed LNA to be operating at 2.45GHz . i run the simulation on typical corners and results were coming good. But when i ran on other process corners it got fail at two values typically rather than tuning to 2.45GHz the circuit get tuned to 2.55GHz.
now i am planning to redesign my circuit and was thinking of including the matching network at the input.
and trying to include pi matching network because of its advantage of high Q and low inductor values.
But i am confused how to select the RF inductor that gives maximum Q as their is no option available in Rf model library that defines Q of inductor

Title: Re: Process_corners
Post by aaron_do on Apr 16^th, 2012, 5:39pm

Hi,

there are many papers on IEEExplore which discuss the Q of an inductor and they are worth reading. Also, if you want the best Q factor for your inductors, you should be designing your own inductors, and modeling them using some EM tool such as ADS momentum. This will also allow you to model other critical traces surrounding the LNA etc...

As for your choice of pi network, when they say it has high Q it means that the bandwidth is narrow. It will be lossier than a simple L-match. Also, you already mentioned that the LNA tuning was off over corners, so why don't you consider a broader bandwidth matching such as a transformer.

You should also consider than the center frequency of your matching network may not be the same as the center frequency of your LNA since the input impedance is capacitive.

regards,
Aaron