How to calculate current coefficinets from s-parameters?

For Chebyshev current distribution of an array antenna elements, how to recheck the current distribution (ratio) given only the s-Parameters ?
In another words, is mag(s31)^2 / mag(s21)^2 = I3/I2 or is it mag(s31)/mag(s21)=I3/I2 ? , ANY relating paper or equation plz :)
Many Thanks in advance

mag(s31)/mag(s21) is a scalar voltage gain relation between port 2 and port 3 and i think the current is linked with Z0. And in your first case it should be square root for current and voltage.

Isn't mag(s31)^2 / mag(s21)^2 = power@port3 / power@port2 !
that is, mag(s31)^2 = mag(s21)^2 =V3*I3/V2*I2 ,and for parallel corporate feeding network for the array elements, we may cancel V2 and V3 together, having at the end,
mag(s31)^2 = mag(s21)^2 =I3/I2 , is that right or i am missing something ?!
Many Thanks for your time and help :)

You are right: the relation mag(s31)^2 / mag(s21)^2 = power@port3 / power@port2 equals the current relation mag(s31)^2 = mag(s21)^2 =I3/I2.