[SOLVED] coupling factor and loss of a transformer

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rfcn

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Do the coupling factor and loss of a transformer mean the same thing? We can use s-paramter simulation to get the loss of the transformer. How can we simulate the coupling factor of a transformer with s-paramter file?
 

No they are not the same thing, but when doing a system analysis can see the coupling factor as a loss in the budget of the system.
 

Convert the S parameters to Z parameters.

Then:
L1=Im[Z11]/2/pi/f
L2=Im[Z22]/2/pi/f
M=Im[Z21]/2/pi/f
K=M/sqrt(L1*L2)

K is the coupling factor.
 

shlomo22 said:
Convert the S parameters to Z parameters.

Then:
L1=Im[Z11]/2/pi/f
L2=Im[Z22]/2/pi/f
M=Im[Z21]/2/pi/f
K=M/sqrt(L1*L2)

K is the coupling factor.
Click to expand...

Hi, shlomo22,

Thanks for your answer! Do you have any reference paper or document on this?

According to my knowlage, to caluculate inductance we should use Y parameter as:
L1 = Im[1/Y11]/2/pi/f
L2 = Im[1/Y22]/2/pi/f
It should be differenct with that calculated by Z parameter. For a two-port network, Z11 != Zin. So, I don't think the first two equations for inductance calculation is corrent until you provide some reference.

regards,
rfcn
 

The equations for two-port Z parameters are:
V1=Z11*I1+Z12*I2
V2=Z21*I1+Z22*I2

The equations for an ideal transformer are:
V1=jwL1*I1+jwM*I2
V2=jwM*I1+jwL2*I2

The two sets of equations have the same form.

For a single inductor, you can used either Y-parameter or Z-parameter equations, they give the same result because it's a one-port situation and you are inverting a number not a matrix.
 

    rfcn

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