modeling a metal plate with a conductivity

Hello,
I am modeling a metal plate with a conductivity of 1e7 S / m in hfss, I wish to use the principle of finite conductuity by unsealing solve inside. I do not find the solution to model that the surface of the plate with a finished conductivity instead of meshing all the plate, the boundary conditions are of master_slave
You have answers please

The basic idea is the same as metal model in Method of Moments EM solvers: for high frequency, use skin depth and calculate the effective surface impedance. At lower frequency (large skin depth), you need to consider the conductor thickness also.