How transform S-parameter to A-parameter

[Hidefi]

Hi.

I have a Measured S11-parameter and would like to know how can I transform it to A-Parameter. Will be used to remove the effect of the SMA conector and then the input impedance of my RFID antenna will be obtain.

Thanks in advance

 

[BigBoss]

Use Matlab or ADS...

 

[Hidefi]

Thanks, but in matlab, function s2abcd needs S11, S12, S21, S22 parameters. for example:

s_par=[abs(0.8413 + 0.3280i) , 0 ; 0 , 0];
Apar=s2abcd(s_par,50);

Apar =

Inf + Infi
Inf - Infi

;

I have only S11, for a one port network how can I transform?

my reference "RFID Tag Antenna Design and its EM Simulation. Based Measurement Method"

 

[pavel_adameyko]

As i understand you have ABCD params of SMA connector. In such case, first, you should calculate input impedance of antenna with SMA
R1 = Ro(1+S11)/(1-S11), then antenna impedance without SMA would be R2 = (D*R1-B)/(A-C*R1) - if i'm not mistaken, where A,B,C,D - a params of SMA connector.
Regards.