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What is Noise Format In *.S2P file?

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Oct 3, 2002
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I found In S2P file ,the first part is declare,the second is S-para,but in the third part,I do not understand it means,I know it is noise para,but what is it mean? the first row of it is freq,but what is and the second,third,..row?
thank u


Page 3 of this document shows the parameters **broken link removed**

They involve the lowest noise figure and the source impedance that produces it.

Here is a screen shot of that part of the document.
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Just one thing to add to S2P(SnP) files, is that the formats can be different.

Default Option Line
The default option line for component data files is:

# GHZ S MA R 50

Option Line Examples
Frequency in GHz, S-parameters in real-imaginary format, normalized 100 ohms:

# GHz S RI R 100

Frequency in KHz, Y-parameters in real-imaginary format, normalized 100 ohms:

# KHz Y RI R 100

Frequency in Hz, Z-parameters in magnitude-degree format, normalized to 1 ohm:

# Hz Z MA R 1

Frequency in KHz, H-parameters in real-imaginary format normalized to 1 ohm:

# KHz H RI R 1

Frequency in Hz, G-parameters in magnitude-degree, format normalized to 1 ohm:

# Hz G MA R 1

RI = Real and Imaginary
MA = Mag and Angle

as for noise.

Adding Noise Parameters to an SnP File
Noise parameters can be included in SnP 2-port data files. Noise data can follow G-, H-, S-, Y-, or Z-parameters described for each frequency. The x values are data.

Each line of a noise parameter has the following five entries:

x1 x2 x3 x4 x5


x1 = Frequency in units. The first point of noise data must have a frequency less than the frequency of the last S-parameter frequency

x2 = Minimum noise figure in dB

x3 = Source reflection coefficient to realize minimum noise figure (MA)

x4 =Phase in degrees of the reflection coefficient (MA)

x5 =Normalized effective noise resistance. The system simulator requires this parameter to meet physical requirements. If the user-supplied x5 value is less than allowed for this requirement, then the system simulator will force this x5 value to the lowest physical limit.

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the X1 description in the previous post is very important. The CAD program can only tell if the noise lines are noise if the frequency goes back down compared to the previous two port parameter data lines.

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