Understanding S parameters

[goldsmith]

Dear Friends!
Hello
I want to know that what are the S parameters and when we will use them and how we can use them.( and what are their applications?)
With Appreciate
Goldsmith

 

[covcst]

S parameters are only used in microwave domain......u need to go through the book by Pozar to have some preliminary idea.......

 

[goldsmith]

Dear covcst
Hi
Thank you for your reply.
Is it possible that you introduce to me some books that i can see it's describe in that , please?( as simple as possible)
Thanks in advance
Goldsmith

 

[mig-11101]

Hi!
Try wiki, there is pretty good info about s-parameters! Scattering parameters - Wikipedia, the free encyclopedia

S params. describe incident and output waves. S11 describes reflection from system to the source, S22 describes reflection from load back to system, S21 - system gain (transmission from source to load), S12 is reverse S21.

There should be defined load and source impedance in order to work with S parameters.

About applications - benefit of S-parameters is that they are being measured on fixed impedances(50ohm usualy) at input/output, other systems (h,y,z) requires short/open for measures, and this makes it complex when working on high frequencies. S parameters are easy to measure at microwaves.

 

[ninju]

At microwave frequencies, you can't use ABCD or h parameters or Z or y parameters, because you can't open circuit it easily.So, you measure in terms of power input at this port when other ports satisfy some conditions (eg, matched terminated, etc). This leads to the s parameters. Yeah, pozar is a good book. So's ludwig. also refer RF system book by Thomas Lee.