S-parameter

Can anybody give me any paper or information about how to use S-parameter in measuring simple circuit? I've read S-parameter is for stability analysis, the small signal analysis is more important as it can tell you more about your deisgn performance such as gain and freq response! Is that true?

A brief explanation with sample is a good infromation! :D

S parameters are just another type of two port parameters like Z, Y, and h. You can use them to determine any two port parameter like gain given a source and load impedance and port input impedance given a load on the other port.

What makes them so useful is that the ports are terminated in a resistive value instead of a short or open. At higher frequencies shorts and opens are hard to make and sometimes make the active device oscillate.

What makes them so useful is that the ports are terminated in a resistive value instead of a short or open. At higher frequencies shorts and opens are hard to make and sometimes make the active device oscillate - flatulent

So, S-parameter is suitable for any freq analysis? What is your suggestion on doing analysis? Small signal/S-parameter/Tow-port analysis?

Do you have a good paper or source which tell more about S-parameter?

Hi

the s-parameter analysis is suitable for frequency from 1 MHz to 100 GHz and up. The problem is what do you want? If you want to see the gain (s21), the isolation (s12), the input/output impedance (single and/or differenciale) this approch is good. If you want to see the NF or other parameters it is not good. I don't know if you are a designer or an application, but take in account that the s-parameter are defined as wave energy division, so you have to do attention when you use them.
You can find a lot of information in the application note of the agilent site.

By

Hi

S-Parameters are most commonly used to define Reflectance and Transmittance of the signal in Two port network. S11 is used for reflection. S21 is used for transmittance. Normally we plot S11 and S21 versus frequency in designing of the coupled resonator or filters. These parameters giva a very good notion of the circuit performance at various frequencies.

Faisal

One more point.
There is no circuit that has no S parameters, opposite to the low freq. e.g. Z , H ,etc parameters, where the elements of the matrix may be infinite, so not usable.

you say that

Can you explain why the matrix might be infinite ? (for two port circuit) Do you mean for every frequency. there would be 4 paramters for h,z,y,..etc matrixes for two port circuit. But in practice open or short circuiting the ports may cause osc. So, these paramters can not be measured for high frequencies. And in practice there is no such infinite matrix elememts for h,y,z, etc.

Hi all,
That is the best paper of S-parameters (Agilent paper).

Regards,
Dienal

Or a direct link for the AN-154 S parameters app.note, as above
http://cp.literature.agilent.com/lit.../5952-1087.pdf
g579

S-parameter is to high frequency as h-parameters is to Low frequency;
these parameters basically characterise any component (active or passive) at high frequencies 1GHz and beyond ; The measurement of currents and voltages is not possible at high frequencies as can be done at lower frequencies and since the only electrical quantity that is measurable at higher frequencies is POWER; The S-parameters are thus based on measurement of RF power utilising resistive termination conditions instead of short/open terminations used in low frequency measurements

i am also a new man in RF design ,thank you for your resoure