how to find the y parameter of microstrio gap

hi friends.....The Figure shows a layout of a microstrip gap for EM simulation, where arrows indicate the reference planes for de-embedding to obtain the two-port Y parameters of the microstrip gap.how to do this using ads..and how to determine the dimension of the microstrip gap .....whether we can use ads....if so i need exact steps to do this process..... i need to know this urgently....
with kind regards,
yamini.