how can i set the lumped port for ltcc capacitor?

I draw a embedded multilay capacitor ,then i
set two lumped port at each side of capacitor,but when use the formule
c=-1/(2*pi*freq*im(Z(11))),
I got nagetive value .
how can i solve this problem?

I guess your C equation is incorrect.
please try:
C=im(Y11)/(2*pi*freq)

thank you
but the two formules express the same mean and value .

Those two formular represent different meaning, Y(1,1) is not equal to 1/Z(1,1).

For two lumped ports simulation, you need check whether two ports share common reference ground plane.

Regards,