S-parameter measurements with active probe

Hi everyone,

a measurement question today: is it possible to measure the S11 parameter of an RF circuit using an active probe and a network analyser?
To me the active probe can only measure the S21 parameter but I'm not sure yet...

Thanx
Ghost

you are not supposed to do it. active probe in not 50 Ohm match. it is for spectrum analyzer, and debuggin purpose only.

That what I was thinking...it doesn't make sense. S parameter measurement on wafer is thus realized with passvie probes?