S-Parameters playlist.
https://www.youtube.com/watch?v=_p0efFhCt6I&list=PLFxhgwM1F4yyAu86pAYE5KTppq0xZ8NFr
DUT Performance: How to Use Scattering S-Parameters for RF Circuit Analysis.
S (Scattering) Parameter
By definition, an S Parameter is the ratio of the voltage, both magnitude and phase, of a signal “coming out” of a network port to that of the signal “going into” the port. Source & load impedances are 50 ohms.
The S Parameter of a device can be plotted on a Smith Chart or Polar Plot to show changes with respect to frequency.
it varies with biasing conditions
it varies with frequency
S Parameters for a 2-port network
a1 & a2 are incident wave
b1 & b2 are reflected wave
S11= input reflection coefficient
S12= reverse transmission coefficient
S21= forward transmission coefficient
S22= output reflection coefficient
The Scattering matrix is a mathematical construct that quantifies how RF energy propagates through a multi-port network. The S Parameter is what allows us to accurately describe the properties of complicated networks as simple "black boxes". For an RF signal incident on one port, some fraction of that signal gets reflected back out of the incident port, some of it enters into the incident port and then exits at (or scatters to) some or all of the other ports (perhaps being amplified or attenuated).
If either port is terminated with the characteristic impedance, the reflection term for a signal sent to that port becomes zero. Thus, if port 2 is terminated in Zo and an incident signal applied to port 1:
If either port is terminated with the characteristic impedance, the reflection term for a signal sent to that port becomes zero. Thus, if port 2 is terminated in Zo and an incident signal applied to port 1: