Noise parameters

Updated January 18, 2010

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Noise parameters are an important concept in designing low noise amplifiers.

Noise parameters are a way to predict the signal to noise ratio of an active device, based on the impedance match it sees. Designing a low noise amplifier is not as easy as matching the input for lowest VSWR.

There are three noise parameters, four if you count real and imaginary parts of the first one:

Gamma_Opt: the reflection coefficient, seen by the device, which provides the best NF performance

R_N: the equivalent noise "resistance"

F_MIN: the noise figure you will attain when the device sees GammaOpt