transform s parameter get from cst simulationto abcd

hi all
i want to transform s parameter which i get from cst to abcd parameter . i dont know whether i should use unwrapped phase or wrapped one? and also linear s parameter or sparameter in db?

Look into pozar chapter 4, there is conversion formulaes that are given in that book for S parameters to ABCD, and u will have to take the values in magnitude , not in dBs..!