S-Parameters have been with us a long time but few of us really have a good feel for them.
A modern RF engineer would be "up the creek" if he or she could not manipulate / use
/ and understand s-parameters.
This page provides links to s-parameter tutorials, application examples, s-parameter tools /
demos and manufacturer's s-parameter data files. We hope you will find enough material here
to help you get over any "fear" of this important subject!
Scattering Parameters, or s-parameters, are the reflection and transmission coefficients between
the incident and reflection waves. They describe completely the behavior of
a device under linear conditions at microwave frequency range. Each parameter
is typically characterized by magnitude, decibel and phase. The expression
in decibel is 20log(Sij) because s-parameters are voltage ratios of the waves.
S11: input reflection coefficient of 50W terminated output. S21: forward transmission coefficient of 50W terminated output. S12: reverse transmission coefficient of 50W terminated input. S22: output reflection coefficient of 50W terminated input.
The advantage of s-parameters does not only lie in the complete description
of the device performance at microwave frequencies but also the ability to
convert to other parameters such as hybrid (H) or admittance (Y) parameters.
Additionally, stability factor (K) and many gain parameters can be computed
using the following equations:
Agilent's Wireless Design Tips, including application notes and other literature
to help the designer. To get here from the link, press "Library" in the small
blue box, then "Wireless Library" and scroll down to the bottom