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.
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.