Calculating reflection coefficient of a multi-layer structure using HFSS

Hi everyone,
I want to simulate a model described in a paper. But my simulation result isn?t the same with that in the paper. I?m not sure how to enter the complex relative permittivity. The real part is 9.52, and the imaginary is 5.27. Is the setup right in figure1 attached? The air box include the multi-layer structure without air gap.
Thank you in advance!

Imaginary permittivity is an alternative way to specify dielectric loss tangent. You should be able to derive the relation reviewing your text books.

Thank you for your reply! Could you write it more clearly? Thank you!