Transmission and Reflection coefficient from S parameter

时间：04-08 整理：3721RD 点击：

Hi Friends....
Can anyone give the relation between Transmission ,reflection coefficient and s parameter.

In my case load is not perfectly matched.
I know one equation for Reflection coefficent
Γin=S11+( S12*S21*ΓL)/(1-S22*ΓL)
But how to find out ΓL

Thanks in advance
Nijas

ΓL=S22+( S12*S21*Γin)/(1-S11*Γin)

my main target is how to find out Γin.

Finding Reflection and Transmission coefficent from other paramter also helpfull for my calculation....

Thanks for your replay....
Nijas

For single frequency one can calculate Γin as per the equation above.
So you need to have ΓL and S-para data.
ΓL for 50 ohm char impedance will be (ZL-50)/(ZL+50).
where ZL is load impedance.
ΓL=S22+( S12*S21*Γin)/(1-S11*Γin) equation is valid when there is DUT with bi-directional behavior like amplifier etc.
In this case ΓL is depend on Γin and vice varsa.

Hope this will help you

Can you give any formula for Transmission coefficient....:D

1-ΓL

Input reflection coefficient is S11,
Output reflection coefficient ( that is ration of power reflected from load to power transmitted towards load)
Transmission coefficient is S12 or you can say isolation
& S21 is gain.

Read book by Gonzalez
Microwave transistor amplifiers.

It does not make any sense if we simply tell the formular from books. You'd better read them yourself. There are many books you can refer to, such as "Microwave Eningeering" and "RF Circuit Design".

can any one tell me what are s parameters of amplifier n what there values tell about for eg if S11 is input impedance and for rf amplifier it should be less that -10db so why is that so? if u have some links or tutorials so plz refer.