Thanks to you both for ur suggestions.
I have done these both things but not enough.
In line calc, we can change the material properties but how to change the bottom conductor? and the Z(not) defined there is characterstic impedence or intrinsic impedence? other problem is how to determine capacitance b/w microstrip and the bottom conductor? In ADS, how can we check input impedence while a voltage is applied on input because in this case, all s-param become changed? please send me something more on these probllems. and thanks for the document dear.