Capacitance Using S-parameters

Hi,I have the frqunency and the S parameters of two-port series network.How can I calculate the capacitance from the previous given information?
I designed my capacitor and I put it undertest by VNA ,but what the VNA gave me are the s11,s12,s21,s22 an lists of frequencies.but how can I get my capacitance?

Hello electronicman,


It is very easy Simple to calculate.... use equation 2
Get the Y parameters from S-parameters then follow the equations...

Series Capacitance (pF) of a series RC network
C=-1.0E12 / ( 2*PI * FREQ * imag( 1 / Y11 ) ) in pF -----equation 1

Series Capacitance (pF) between any pair of ports assuming PI-model
C=1.0E12 / ( 2*PI * FREQ * imag( 1 / Y21 ) ) in pF-----equation 1

The Quality Factor (Q) based on single port
Q=mag( imag( Y11 ) / real( Y11 ) )


Use Sonnet Lite Free version to import the S-parameters then
plot the C & Q required....


---manju--