Relection Group Delay equation

Hello All,


If any one knows or has details on one port circuit Group Delay measurement equation (reflection group delay) prefrably using S-parameters... please send me.....

Note: I have the two port circuit GD measurement details...



---manju--

As far as i know it is related to phase of S21(antenna, filters etc). Any way u can calculate group leay
GD=-(chage of phase)/(Change in frequency)